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gerrit-public.fairphone.software / toolchain / llvm-project / 742052526a5c525031f506ff597e872c745ab73f / . / llvm / docs / LangRef.html
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4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
Reid Spencercb84e432004-08-26 20:44:00 +0000[diff] [blame]6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
7 <meta name="author" content="Chris Lattner">
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]8 <meta name="description"
Reid Spencercb84e432004-08-26 20:44:00 +0000[diff] [blame]9 content="LLVM Assembly Language Reference Manual.">
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]10 <link rel="stylesheet" href="llvm.css" type="text/css">
11</head>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]14
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]15<div class="doc_title"> LLVM Language Reference Manual </div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a>
24 <ol>
Bill Wendling8693ef82009-07-20 02:41:50 +0000[diff] [blame]25 <li><a href="#linkage_private">'<tt>private</tt>' Linkage</a></li>
26 <li><a href="#linkage_linker_private">'<tt>linker_private</tt>' Linkage</a></li>
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]27 <li><a href="#linkage_linker_private_weak">'<tt>linker_private_weak</tt>' Linkage</a></li>
Bill Wendling578ee402010-08-20 22:05:50 +0000[diff] [blame]28 <li><a href="#linkage_linker_private_weak_def_auto">'<tt>linker_private_weak_def_auto</tt>' Linkage</a></li>
Bill Wendling8693ef82009-07-20 02:41:50 +0000[diff] [blame]29 <li><a href="#linkage_internal">'<tt>internal</tt>' Linkage</a></li>
30 <li><a href="#linkage_available_externally">'<tt>available_externally</tt>' Linkage</a></li>
31 <li><a href="#linkage_linkonce">'<tt>linkonce</tt>' Linkage</a></li>
32 <li><a href="#linkage_common">'<tt>common</tt>' Linkage</a></li>
33 <li><a href="#linkage_weak">'<tt>weak</tt>' Linkage</a></li>
34 <li><a href="#linkage_appending">'<tt>appending</tt>' Linkage</a></li>
35 <li><a href="#linkage_externweak">'<tt>extern_weak</tt>' Linkage</a></li>
Chris Lattner80d73c72009-10-10 18:26:06 +0000[diff] [blame]36 <li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</tt>' Linkage</a></li>
Bill Wendling8693ef82009-07-20 02:41:50 +0000[diff] [blame]37 <li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
38 <li><a href="#linkage_external">'<tt>externally visible</tt>' Linkage</a></li>
39 <li><a href="#linkage_dllimport">'<tt>dllimport</tt>' Linkage</a></li>
40 <li><a href="#linkage_dllexport">'<tt>dllexport</tt>' Linkage</a></li>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]41 </ol>
42 </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]43 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]44 <li><a href="#namedtypes">Named Types</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]45 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]46 <li><a href="#functionstructure">Functions</a></li>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]47 <li><a href="#aliasstructure">Aliases</a></li>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]48 <li><a href="#namedmetadatastructure">Named Metadata</a></li>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]49 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]50 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]51 <li><a href="#gc">Garbage Collector Names</a></li>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]52 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]53 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]54 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]55 <li><a href="#volatile">Volatile Memory Accesses</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]56 </ol>
57 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]58 <li><a href="#typesystem">Type System</a>
59 <ol>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]60 <li><a href="#t_classifications">Type Classifications</a></li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]61 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]62 <ol>
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]63 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]64 <li><a href="#t_floating">Floating Point Types</a></li>
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]65 <li><a href="#t_x86mmx">X86mmx Type</a></li>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]66 <li><a href="#t_void">Void Type</a></li>
67 <li><a href="#t_label">Label Type</a></li>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]68 <li><a href="#t_metadata">Metadata Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]69 </ol>
70 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]71 <li><a href="#t_derived">Derived Types</a>
72 <ol>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]73 <li><a href="#t_aggregate">Aggregate Types</a>
74 <ol>
75 <li><a href="#t_array">Array Type</a></li>
76 <li><a href="#t_struct">Structure Type</a></li>
77 <li><a href="#t_pstruct">Packed Structure Type</a></li>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]78 <li><a href="#t_vector">Vector Type</a></li>
79 </ol>
80 </li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]81 <li><a href="#t_function">Function Type</a></li>
82 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]83 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]84 </ol>
85 </li>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]86 <li><a href="#t_uprefs">Type Up-references</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]87 </ol>
88 </li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]89 <li><a href="#constants">Constants</a>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]90 <ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]91 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]92 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]93 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
94 <li><a href="#undefvalues">Undefined Values</a></li>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]95 <li><a href="#trapvalues">Trap Values</a></li>
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]96 <li><a href="#blockaddress">Addresses of Basic Blocks</a></li>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]97 <li><a href="#constantexprs">Constant Expressions</a></li>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]98 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]99 </li>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]100 <li><a href="#othervalues">Other Values</a>
101 <ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]102 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]103 <li><a href="#metadata">Metadata Nodes and Metadata Strings</a></li>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]104 </ol>
105 </li>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]106 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
107 <ol>
108 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]109 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
110 Global Variable</a></li>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]111 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
112 Global Variable</a></li>
113 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
114 Global Variable</a></li>
115 </ol>
116 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]117 <li><a href="#instref">Instruction Reference</a>
118 <ol>
119 <li><a href="#terminators">Terminator Instructions</a>
120 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]121 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
122 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]123 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]124 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]125 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]126 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]127 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]128 </ol>
129 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]130 <li><a href="#binaryops">Binary Operations</a>
131 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]132 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]133 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]134 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]135 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]136 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]137 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]138 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
139 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
140 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]141 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
142 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
143 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]144 </ol>
145 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]146 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
147 <ol>
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]148 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
149 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
150 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]151 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]152 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]153 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]154 </ol>
155 </li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]156 <li><a href="#vectorops">Vector Operations</a>
157 <ol>
158 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
159 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
160 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]161 </ol>
162 </li>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]163 <li><a href="#aggregateops">Aggregate Operations</a>
164 <ol>
165 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
166 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
167 </ol>
168 </li>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]169 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]170 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]171 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]172 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
173 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
174 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]175 </ol>
176 </li>
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]177 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]178 <ol>
179 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
180 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
181 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
182 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
183 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]184 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
185 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
186 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
187 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]188 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
189 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]190 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]191 </ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]192 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]193 <li><a href="#otherops">Other Operations</a>
194 <ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]195 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
196 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]197 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]198 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]199 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]200 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]201 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]202 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]203 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]204 </li>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]205 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]206 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]207 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
208 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]209 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
210 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
211 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]212 </ol>
213 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]214 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
215 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]216 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
217 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
218 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]219 </ol>
220 </li>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]221 <li><a href="#int_codegen">Code Generator Intrinsics</a>
222 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]223 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
224 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
225 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
226 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
227 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
228 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
Dan Gohmane58f7b32010-05-26 21:56:15 +0000[diff] [blame]229 <li><a href="#int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswellaa1c3c12004-04-09 16:43:20 +0000[diff] [blame]230 </ol>
231 </li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]232 <li><a href="#int_libc">Standard C Library Intrinsics</a>
233 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]234 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
235 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
236 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
237 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
238 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]239 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
240 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
241 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]242 </ol>
243 </li>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]244 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]245 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]246 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]247 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
248 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
249 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]250 </ol>
251 </li>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]252 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
253 <ol>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]254 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
255 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
256 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
257 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
258 <li><a href="#int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]259 <li><a href="#int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]260 </ol>
261 </li>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]262 <li><a href="#int_fp16">Half Precision Floating Point Intrinsics</a>
263 <ol>
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]264 <li><a href="#int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a></li>
265 <li><a href="#int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a></li>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]266 </ol>
267 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]268 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]269 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]270 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]271 <ol>
272 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]273 </ol>
274 </li>
Bill Wendlingf85850f2008-11-18 22:10:53 +0000[diff] [blame]275 <li><a href="#int_atomics">Atomic intrinsics</a>
276 <ol>
277 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
278 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
279 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
280 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
281 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
282 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
283 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
284 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
285 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
286 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
287 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
288 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
289 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
290 </ol>
291 </li>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]292 <li><a href="#int_memorymarkers">Memory Use Markers</a>
293 <ol>
294 <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
295 <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
296 <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
297 <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
298 </ol>
299 </li>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]300 <li><a href="#int_general">General intrinsics</a>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]301 <ol>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]302 <li><a href="#int_var_annotation">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]303 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]304 <li><a href="#int_annotation">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]305 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]306 <li><a href="#int_trap">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]307 '<tt>llvm.trap</tt>' Intrinsic</a></li>
308 <li><a href="#int_stackprotector">
309 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]310 <li><a href="#int_objectsize">
311 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]312 </ol>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]313 </li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]314 </ol>
315 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]316</ol>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]317
318<div class="doc_author">
319 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
320 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]321</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]322
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]323<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]324<div class="doc_section"> <a name="abstract">Abstract </a></div>
325<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]326
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]327<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]328
329<p>This document is a reference manual for the LLVM assembly language. LLVM is
330 a Static Single Assignment (SSA) based representation that provides type
331 safety, low-level operations, flexibility, and the capability of representing
332 'all' high-level languages cleanly. It is the common code representation
333 used throughout all phases of the LLVM compilation strategy.</p>
334
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]335</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]336
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]337<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]338<div class="doc_section"> <a name="introduction">Introduction</a> </div>
339<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]340
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]341<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]342
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]343<p>The LLVM code representation is designed to be used in three different forms:
344 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
345 for fast loading by a Just-In-Time compiler), and as a human readable
346 assembly language representation. This allows LLVM to provide a powerful
347 intermediate representation for efficient compiler transformations and
348 analysis, while providing a natural means to debug and visualize the
349 transformations. The three different forms of LLVM are all equivalent. This
350 document describes the human readable representation and notation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]351
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]352<p>The LLVM representation aims to be light-weight and low-level while being
353 expressive, typed, and extensible at the same time. It aims to be a
354 "universal IR" of sorts, by being at a low enough level that high-level ideas
355 may be cleanly mapped to it (similar to how microprocessors are "universal
356 IR's", allowing many source languages to be mapped to them). By providing
357 type information, LLVM can be used as the target of optimizations: for
358 example, through pointer analysis, it can be proven that a C automatic
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]359 variable is never accessed outside of the current function, allowing it to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]360 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]361
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]362</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]363
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]364<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]365<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]366
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]367<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]368
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]369<p>It is important to note that this document describes 'well formed' LLVM
370 assembly language. There is a difference between what the parser accepts and
371 what is considered 'well formed'. For example, the following instruction is
372 syntactically okay, but not well formed:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]373
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]374<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]375%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]376</pre>
377
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]378<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
379 LLVM infrastructure provides a verification pass that may be used to verify
380 that an LLVM module is well formed. This pass is automatically run by the
381 parser after parsing input assembly and by the optimizer before it outputs
382 bitcode. The violations pointed out by the verifier pass indicate bugs in
383 transformation passes or input to the parser.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]384
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]385</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]386
Chris Lattner87a3dbe2007-10-03 17:34:29 +0000[diff] [blame]387<!-- Describe the typesetting conventions here. -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]388
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]389<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]390<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]391<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]392
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]393<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]394
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]395<p>LLVM identifiers come in two basic types: global and local. Global
396 identifiers (functions, global variables) begin with the <tt>'@'</tt>
397 character. Local identifiers (register names, types) begin with
398 the <tt>'%'</tt> character. Additionally, there are three different formats
399 for identifiers, for different purposes:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]400
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]401<ol>
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]402 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]403 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
404 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
405 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
406 other characters in their names can be surrounded with quotes. Special
407 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
408 ASCII code for the character in hexadecimal. In this way, any character
409 can be used in a name value, even quotes themselves.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]410
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]411 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]412 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]413
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]414 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]415 constants</a>, below.</li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]416</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]417
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]418<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]419 don't need to worry about name clashes with reserved words, and the set of
420 reserved words may be expanded in the future without penalty. Additionally,
421 unnamed identifiers allow a compiler to quickly come up with a temporary
422 variable without having to avoid symbol table conflicts.</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]423
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]424<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]425 languages. There are keywords for different opcodes
426 ('<tt><a href="#i_add">add</a></tt>',
427 '<tt><a href="#i_bitcast">bitcast</a></tt>',
428 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
429 ('<tt><a href="#t_void">void</a></tt>',
430 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
431 reserved words cannot conflict with variable names, because none of them
432 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]433
434<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]435 '<tt>%X</tt>' by 8:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]436
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]437<p>The easy way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]438
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]439<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]440%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]441</pre>
442
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]443<p>After strength reduction:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]444
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]445<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]446%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]447</pre>
448
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]449<p>And the hard way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]450
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]451<pre class="doc_code">
Gabor Greifbd0328f2009-10-28 13:05:07 +0000[diff] [blame]452%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
453%1 = <a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]454%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]455</pre>
456
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]457<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
458 lexical features of LLVM:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]459
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]460<ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]461 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]462 line.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]463
464 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]465 assigned to a named value.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]466
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]467 <li>Unnamed temporaries are numbered sequentially</li>
468</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]469
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]470<p>It also shows a convention that we follow in this document. When
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]471 demonstrating instructions, we will follow an instruction with a comment that
472 defines the type and name of value produced. Comments are shown in italic
473 text.</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]474
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]475</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]476
477<!-- *********************************************************************** -->
478<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
479<!-- *********************************************************************** -->
480
481<!-- ======================================================================= -->
482<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
483</div>
484
485<div class="doc_text">
486
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]487<p>LLVM programs are composed of "Module"s, each of which is a translation unit
488 of the input programs. Each module consists of functions, global variables,
489 and symbol table entries. Modules may be combined together with the LLVM
490 linker, which merges function (and global variable) definitions, resolves
491 forward declarations, and merges symbol table entries. Here is an example of
492 the "hello world" module:</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]493
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]494<pre class="doc_code">
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]495<i>; Declare the string constant as a global constant.</i>&nbsp;
496<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>&nbsp;
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]497
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]498<i>; External declaration of the puts function</i>&nbsp;
499<a href="#functionstructure">declare</a> i32 @puts(i8*) <i>; i32 (i8*)* </i>&nbsp;
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]500
501<i>; Definition of main function</i>
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]502define i32 @main() { <i>; i32()* </i>&nbsp;
503 <i>; Convert [13 x i8]* to i8 *...</i>&nbsp;
504 %cast210 = <a href="#i_getelementptr">getelementptr</a> [13 x i8]* @.LC0, i64 0, i64 0 <i>; i8*</i>&nbsp;
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]505
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]506 <i>; Call puts function to write out the string to stdout.</i>&nbsp;
507 <a href="#i_call">call</a> i32 @puts(i8* %cast210) <i>; i32</i>&nbsp;
508 <a href="#i_ret">ret</a> i32 0&nbsp;
509}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]510
511<i>; Named metadata</i>
512!1 = metadata !{i32 41}
513!foo = !{!1, null}
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]514</pre>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]515
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]516<p>This example is made up of a <a href="#globalvars">global variable</a> named
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]517 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]518 a <a href="#functionstructure">function definition</a> for
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]519 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
520 "<tt>foo"</tt>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]521
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]522<p>In general, a module is made up of a list of global values, where both
523 functions and global variables are global values. Global values are
524 represented by a pointer to a memory location (in this case, a pointer to an
525 array of char, and a pointer to a function), and have one of the
526 following <a href="#linkage">linkage types</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]527
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]528</div>
529
530<!-- ======================================================================= -->
531<div class="doc_subsection">
532 <a name="linkage">Linkage Types</a>
533</div>
534
535<div class="doc_text">
536
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]537<p>All Global Variables and Functions have one of the following types of
538 linkage:</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]539
540<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]541 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]542 <dd>Global values with "<tt>private</tt>" linkage are only directly accessible
543 by objects in the current module. In particular, linking code into a
544 module with an private global value may cause the private to be renamed as
545 necessary to avoid collisions. Because the symbol is private to the
546 module, all references can be updated. This doesn't show up in any symbol
547 table in the object file.</dd>
Rafael Espindola6de96a12009-01-15 20:18:42 +0000[diff] [blame]548
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]549 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]550 <dd>Similar to <tt>private</tt>, but the symbol is passed through the
551 assembler and evaluated by the linker. Unlike normal strong symbols, they
552 are removed by the linker from the final linked image (executable or
553 dynamic library).</dd>
554
555 <dt><tt><b><a name="linkage_linker_private_weak">linker_private_weak</a></b></tt></dt>
556 <dd>Similar to "<tt>linker_private</tt>", but the symbol is weak. Note that
557 <tt>linker_private_weak</tt> symbols are subject to coalescing by the
558 linker. The symbols are removed by the linker from the final linked image
559 (executable or dynamic library).</dd>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]560
Bill Wendling578ee402010-08-20 22:05:50 +0000[diff] [blame]561 <dt><tt><b><a name="linkage_linker_private_weak_def_auto">linker_private_weak_def_auto</a></b></tt></dt>
562 <dd>Similar to "<tt>linker_private_weak</tt>", but it's known that the address
563 of the object is not taken. For instance, functions that had an inline
564 definition, but the compiler decided not to inline it. Note,
565 unlike <tt>linker_private</tt> and <tt>linker_private_weak</tt>,
566 <tt>linker_private_weak_def_auto</tt> may have only <tt>default</tt>
567 visibility. The symbols are removed by the linker from the final linked
568 image (executable or dynamic library).</dd>
569
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]570 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendling36321712010-06-29 22:34:52 +0000[diff] [blame]571 <dd>Similar to private, but the value shows as a local symbol
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]572 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
573 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]574
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]575 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner184f1be2009-04-13 05:44:34 +0000[diff] [blame]576 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]577 into the object file corresponding to the LLVM module. They exist to
578 allow inlining and other optimizations to take place given knowledge of
579 the definition of the global, which is known to be somewhere outside the
580 module. Globals with <tt>available_externally</tt> linkage are allowed to
581 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
582 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner184f1be2009-04-13 05:44:34 +0000[diff] [blame]583
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]584 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]585 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner0de4caa2010-01-09 19:15:14 +0000[diff] [blame]586 the same name when linkage occurs. This can be used to implement
587 some forms of inline functions, templates, or other code which must be
588 generated in each translation unit that uses it, but where the body may
589 be overridden with a more definitive definition later. Unreferenced
590 <tt>linkonce</tt> globals are allowed to be discarded. Note that
591 <tt>linkonce</tt> linkage does not actually allow the optimizer to
592 inline the body of this function into callers because it doesn't know if
593 this definition of the function is the definitive definition within the
594 program or whether it will be overridden by a stronger definition.
595 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
596 linkage.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]597
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]598 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]599 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
600 <tt>linkonce</tt> linkage, except that unreferenced globals with
601 <tt>weak</tt> linkage may not be discarded. This is used for globals that
602 are declared "weak" in C source code.</dd>
603
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]604 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]605 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
606 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
607 global scope.
608 Symbols with "<tt>common</tt>" linkage are merged in the same way as
609 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattner0aff0b22009-08-05 05:41:44 +0000[diff] [blame]610 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]611 must have a zero initializer, and may not be marked '<a
Chris Lattner0aff0b22009-08-05 05:41:44 +0000[diff] [blame]612 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
613 have common linkage.</dd>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]614
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]615
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]616 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]617 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]618 pointer to array type. When two global variables with appending linkage
619 are linked together, the two global arrays are appended together. This is
620 the LLVM, typesafe, equivalent of having the system linker append together
621 "sections" with identical names when .o files are linked.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]622
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]623 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]624 <dd>The semantics of this linkage follow the ELF object file model: the symbol
625 is weak until linked, if not linked, the symbol becomes null instead of
626 being an undefined reference.</dd>
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]627
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]628 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
629 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]630 <dd>Some languages allow differing globals to be merged, such as two functions
631 with different semantics. Other languages, such as <tt>C++</tt>, ensure
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]632 that only equivalent globals are ever merged (the "one definition rule"
633 &mdash; "ODR"). Such languages can use the <tt>linkonce_odr</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]634 and <tt>weak_odr</tt> linkage types to indicate that the global will only
635 be merged with equivalent globals. These linkage types are otherwise the
636 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]637
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]638 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]639 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]640 visible, meaning that it participates in linkage and can be used to
641 resolve external symbol references.</dd>
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]642</dl>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]643
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]644<p>The next two types of linkage are targeted for Microsoft Windows platform
645 only. They are designed to support importing (exporting) symbols from (to)
646 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]647
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]648<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]649 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]650 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]651 or variable via a global pointer to a pointer that is set up by the DLL
652 exporting the symbol. On Microsoft Windows targets, the pointer name is
653 formed by combining <code>__imp_</code> and the function or variable
654 name.</dd>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]655
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]656 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]657 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]658 pointer to a pointer in a DLL, so that it can be referenced with the
659 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
660 name is formed by combining <code>__imp_</code> and the function or
661 variable name.</dd>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]662</dl>
663
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]664<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
665 another module defined a "<tt>.LC0</tt>" variable and was linked with this
666 one, one of the two would be renamed, preventing a collision. Since
667 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
668 declarations), they are accessible outside of the current module.</p>
669
670<p>It is illegal for a function <i>declaration</i> to have any linkage type
671 other than "externally visible", <tt>dllimport</tt>
672 or <tt>extern_weak</tt>.</p>
673
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]674<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]675 or <tt>weak_odr</tt> linkages.</p>
676
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]677</div>
678
679<!-- ======================================================================= -->
680<div class="doc_subsection">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]681 <a name="callingconv">Calling Conventions</a>
682</div>
683
684<div class="doc_text">
685
686<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]687 and <a href="#i_invoke">invokes</a> can all have an optional calling
688 convention specified for the call. The calling convention of any pair of
689 dynamic caller/callee must match, or the behavior of the program is
690 undefined. The following calling conventions are supported by LLVM, and more
691 may be added in the future:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]692
693<dl>
694 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]695 <dd>This calling convention (the default if no other calling convention is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]696 specified) matches the target C calling conventions. This calling
697 convention supports varargs function calls and tolerates some mismatch in
698 the declared prototype and implemented declaration of the function (as
699 does normal C).</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]700
701 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]702 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]703 (e.g. by passing things in registers). This calling convention allows the
704 target to use whatever tricks it wants to produce fast code for the
705 target, without having to conform to an externally specified ABI
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]706 (Application Binary Interface).
707 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattnera179e4d2010-03-11 00:22:57 +0000[diff] [blame]708 when this or the GHC convention is used.</a> This calling convention
709 does not support varargs and requires the prototype of all callees to
710 exactly match the prototype of the function definition.</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]711
712 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]713 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]714 as possible under the assumption that the call is not commonly executed.
715 As such, these calls often preserve all registers so that the call does
716 not break any live ranges in the caller side. This calling convention
717 does not support varargs and requires the prototype of all callees to
718 exactly match the prototype of the function definition.</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]719
Chris Lattnera179e4d2010-03-11 00:22:57 +0000[diff] [blame]720 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
721 <dd>This calling convention has been implemented specifically for use by the
722 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
723 It passes everything in registers, going to extremes to achieve this by
724 disabling callee save registers. This calling convention should not be
725 used lightly but only for specific situations such as an alternative to
726 the <em>register pinning</em> performance technique often used when
727 implementing functional programming languages.At the moment only X86
728 supports this convention and it has the following limitations:
729 <ul>
730 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
731 floating point types are supported.</li>
732 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
733 6 floating point parameters.</li>
734 </ul>
735 This calling convention supports
736 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
737 requires both the caller and callee are using it.
738 </dd>
739
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]740 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]741 <dd>Any calling convention may be specified by number, allowing
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]742 target-specific calling conventions to be used. Target specific calling
743 conventions start at 64.</dd>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]744</dl>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]745
746<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]747 support Pascal conventions or any other well-known target-independent
748 convention.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]749
750</div>
751
752<!-- ======================================================================= -->
753<div class="doc_subsection">
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]754 <a name="visibility">Visibility Styles</a>
755</div>
756
757<div class="doc_text">
758
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]759<p>All Global Variables and Functions have one of the following visibility
760 styles:</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]761
762<dl>
763 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]764 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]765 that the declaration is visible to other modules and, in shared libraries,
766 means that the declared entity may be overridden. On Darwin, default
767 visibility means that the declaration is visible to other modules. Default
768 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]769
770 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]771 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]772 object if they are in the same shared object. Usually, hidden visibility
773 indicates that the symbol will not be placed into the dynamic symbol
774 table, so no other module (executable or shared library) can reference it
775 directly.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]776
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]777 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]778 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]779 the dynamic symbol table, but that references within the defining module
780 will bind to the local symbol. That is, the symbol cannot be overridden by
781 another module.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]782</dl>
783
784</div>
785
786<!-- ======================================================================= -->
787<div class="doc_subsection">
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]788 <a name="namedtypes">Named Types</a>
789</div>
790
791<div class="doc_text">
792
793<p>LLVM IR allows you to specify name aliases for certain types. This can make
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]794 it easier to read the IR and make the IR more condensed (particularly when
795 recursive types are involved). An example of a name specification is:</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]796
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]797<pre class="doc_code">
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]798%mytype = type { %mytype*, i32 }
799</pre>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]800
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]801<p>You may give a name to any <a href="#typesystem">type</a> except
Chris Lattner249b9762010-08-17 23:26:04 +0000[diff] [blame]802 "<a href="#t_void">void</a>". Type name aliases may be used anywhere a type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]803 is expected with the syntax "%mytype".</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]804
805<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]806 and that you can therefore specify multiple names for the same type. This
807 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
808 uses structural typing, the name is not part of the type. When printing out
809 LLVM IR, the printer will pick <em>one name</em> to render all types of a
810 particular shape. This means that if you have code where two different
811 source types end up having the same LLVM type, that the dumper will sometimes
812 print the "wrong" or unexpected type. This is an important design point and
813 isn't going to change.</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]814
815</div>
816
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]817<!-- ======================================================================= -->
818<div class="doc_subsection">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]819 <a name="globalvars">Global Variables</a>
820</div>
821
822<div class="doc_text">
823
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]824<p>Global variables define regions of memory allocated at compilation time
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]825 instead of run-time. Global variables may optionally be initialized, may
826 have an explicit section to be placed in, and may have an optional explicit
827 alignment specified. A variable may be defined as "thread_local", which
828 means that it will not be shared by threads (each thread will have a
829 separated copy of the variable). A variable may be defined as a global
830 "constant," which indicates that the contents of the variable
831 will <b>never</b> be modified (enabling better optimization, allowing the
832 global data to be placed in the read-only section of an executable, etc).
833 Note that variables that need runtime initialization cannot be marked
834 "constant" as there is a store to the variable.</p>
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]835
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]836<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
837 constant, even if the final definition of the global is not. This capability
838 can be used to enable slightly better optimization of the program, but
839 requires the language definition to guarantee that optimizations based on the
840 'constantness' are valid for the translation units that do not include the
841 definition.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]842
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]843<p>As SSA values, global variables define pointer values that are in scope
844 (i.e. they dominate) all basic blocks in the program. Global variables
845 always define a pointer to their "content" type because they describe a
846 region of memory, and all memory objects in LLVM are accessed through
847 pointers.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]848
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]849<p>A global variable may be declared to reside in a target-specific numbered
850 address space. For targets that support them, address spaces may affect how
851 optimizations are performed and/or what target instructions are used to
852 access the variable. The default address space is zero. The address space
853 qualifier must precede any other attributes.</p>
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]854
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]855<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]856 supports it, it will emit globals to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]857
Chris Lattner78e00bc2010-04-28 00:13:42 +0000[diff] [blame]858<p>An explicit alignment may be specified for a global, which must be a power
859 of 2. If not present, or if the alignment is set to zero, the alignment of
860 the global is set by the target to whatever it feels convenient. If an
861 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner4bd85e42010-04-28 00:31:12 +0000[diff] [blame]862 alignment. Targets and optimizers are not allowed to over-align the global
863 if the global has an assigned section. In this case, the extra alignment
864 could be observable: for example, code could assume that the globals are
865 densely packed in their section and try to iterate over them as an array,
866 alignment padding would break this iteration.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]867
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]868<p>For example, the following defines a global in a numbered address space with
869 an initializer, section, and alignment:</p>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]870
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]871<pre class="doc_code">
Dan Gohmanaaa679b2009-01-11 00:40:00 +0000[diff] [blame]872@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]873</pre>
874
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]875</div>
876
877
878<!-- ======================================================================= -->
879<div class="doc_subsection">
880 <a name="functionstructure">Functions</a>
881</div>
882
883<div class="doc_text">
884
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]885<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]886 optional <a href="#linkage">linkage type</a>, an optional
887 <a href="#visibility">visibility style</a>, an optional
888 <a href="#callingconv">calling convention</a>, a return type, an optional
889 <a href="#paramattrs">parameter attribute</a> for the return type, a function
890 name, a (possibly empty) argument list (each with optional
891 <a href="#paramattrs">parameter attributes</a>), optional
892 <a href="#fnattrs">function attributes</a>, an optional section, an optional
893 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
894 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]895
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]896<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
897 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]898 <a href="#visibility">visibility style</a>, an optional
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]899 <a href="#callingconv">calling convention</a>, a return type, an optional
900 <a href="#paramattrs">parameter attribute</a> for the return type, a function
901 name, a possibly empty list of arguments, an optional alignment, and an
902 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]903
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]904<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]905 (Control Flow Graph) for the function. Each basic block may optionally start
906 with a label (giving the basic block a symbol table entry), contains a list
907 of instructions, and ends with a <a href="#terminators">terminator</a>
908 instruction (such as a branch or function return).</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]909
Chris Lattnera59fb102007-06-08 16:52:14 +0000[diff] [blame]910<p>The first basic block in a function is special in two ways: it is immediately
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]911 executed on entrance to the function, and it is not allowed to have
912 predecessor basic blocks (i.e. there can not be any branches to the entry
913 block of a function). Because the block can have no predecessors, it also
914 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]915
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]916<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]917 supports it, it will emit functions to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]918
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]919<p>An explicit alignment may be specified for a function. If not present, or if
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]920 the alignment is set to zero, the alignment of the function is set by the
921 target to whatever it feels convenient. If an explicit alignment is
922 specified, the function is forced to have at least that much alignment. All
923 alignments must be a power of 2.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]924
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]925<h5>Syntax:</h5>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]926<pre class="doc_code">
Chris Lattner0ae02092008-10-13 16:55:18 +0000[diff] [blame]927define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]928 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
929 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
930 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
931 [<a href="#gc">gc</a>] { ... }
932</pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]933
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]934</div>
935
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]936<!-- ======================================================================= -->
937<div class="doc_subsection">
938 <a name="aliasstructure">Aliases</a>
939</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]940
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]941<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]942
943<p>Aliases act as "second name" for the aliasee value (which can be either
944 function, global variable, another alias or bitcast of global value). Aliases
945 may have an optional <a href="#linkage">linkage type</a>, and an
946 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]947
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]948<h5>Syntax:</h5>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]949<pre class="doc_code">
Duncan Sands7e99a942008-09-12 20:48:21 +0000[diff] [blame]950@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]951</pre>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]952
953</div>
954
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]955<!-- ======================================================================= -->
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]956<div class="doc_subsection">
957 <a name="namedmetadatastructure">Named Metadata</a>
958</div>
959
960<div class="doc_text">
961
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]962<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]963 nodes</a> (but not metadata strings) are the only valid operands for
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]964 a named metadata.</p>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]965
966<h5>Syntax:</h5>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]967<pre class="doc_code">
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]968; Some unnamed metadata nodes, which are referenced by the named metadata.
969!0 = metadata !{metadata !"zero"}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]970!1 = metadata !{metadata !"one"}
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]971!2 = metadata !{metadata !"two"}
Dan Gohman58cd65f2010-07-13 19:48:13 +0000[diff] [blame]972; A named metadata.
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]973!name = !{!0, !1, !2}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]974</pre>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]975
976</div>
977
978<!-- ======================================================================= -->
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]979<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]980
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]981<div class="doc_text">
982
983<p>The return type and each parameter of a function type may have a set of
984 <i>parameter attributes</i> associated with them. Parameter attributes are
985 used to communicate additional information about the result or parameters of
986 a function. Parameter attributes are considered to be part of the function,
987 not of the function type, so functions with different parameter attributes
988 can have the same function type.</p>
989
990<p>Parameter attributes are simple keywords that follow the type specified. If
991 multiple parameter attributes are needed, they are space separated. For
992 example:</p>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]993
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]994<pre class="doc_code">
Nick Lewyckydac78d82009-02-15 23:06:14 +0000[diff] [blame]995declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerd2597d72008-10-04 18:33:34 +0000[diff] [blame]996declare i32 @atoi(i8 zeroext)
997declare signext i8 @returns_signed_char()
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]998</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]999
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1000<p>Note that any attributes for the function result (<tt>nounwind</tt>,
1001 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1002
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1003<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1004
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1005<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1006 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1007 <dd>This indicates to the code generator that the parameter or return value
1008 should be zero-extended to a 32-bit value by the caller (for a parameter)
1009 or the callee (for a return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1010
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1011 <dt><tt><b>signext</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1012 <dd>This indicates to the code generator that the parameter or return value
1013 should be sign-extended to a 32-bit value by the caller (for a parameter)
1014 or the callee (for a return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1015
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1016 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1017 <dd>This indicates that this parameter or return value should be treated in a
1018 special target-dependent fashion during while emitting code for a function
1019 call or return (usually, by putting it in a register as opposed to memory,
1020 though some targets use it to distinguish between two different kinds of
1021 registers). Use of this attribute is target-specific.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1022
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1023 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1024 <dd>This indicates that the pointer parameter should really be passed by value
1025 to the function. The attribute implies that a hidden copy of the pointee
1026 is made between the caller and the callee, so the callee is unable to
1027 modify the value in the callee. This attribute is only valid on LLVM
1028 pointer arguments. It is generally used to pass structs and arrays by
1029 value, but is also valid on pointers to scalars. The copy is considered
1030 to belong to the caller not the callee (for example,
1031 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1032 <tt>byval</tt> parameters). This is not a valid attribute for return
1033 values. The byval attribute also supports specifying an alignment with
1034 the align attribute. This has a target-specific effect on the code
1035 generator that usually indicates a desired alignment for the synthesized
1036 stack slot.</dd>
1037
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1038 <dt><tt><b><a name="sret">sret</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1039 <dd>This indicates that the pointer parameter specifies the address of a
1040 structure that is the return value of the function in the source program.
1041 This pointer must be guaranteed by the caller to be valid: loads and
1042 stores to the structure may be assumed by the callee to not to trap. This
1043 may only be applied to the first parameter. This is not a valid attribute
1044 for return values. </dd>
1045
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1046 <dt><tt><b><a name="noalias">noalias</a></b></tt></dt>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1047 <dd>This indicates that pointer values
1048 <a href="#pointeraliasing"><i>based</i></a> on the argument or return
Dan Gohmande256292010-07-02 23:46:54 +0000[diff] [blame]1049 value do not alias pointer values which are not <i>based</i> on it,
1050 ignoring certain "irrelevant" dependencies.
1051 For a call to the parent function, dependencies between memory
1052 references from before or after the call and from those during the call
1053 are "irrelevant" to the <tt>noalias</tt> keyword for the arguments and
1054 return value used in that call.
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1055 The caller shares the responsibility with the callee for ensuring that
1056 these requirements are met.
1057 For further details, please see the discussion of the NoAlias response in
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]1058 <a href="AliasAnalysis.html#MustMayNo">alias analysis</a>.<br>
1059<br>
John McCall72ed8902010-07-06 21:07:14 +0000[diff] [blame]1060 Note that this definition of <tt>noalias</tt> is intentionally
1061 similar to the definition of <tt>restrict</tt> in C99 for function
Chris Lattner5eff9ca2010-07-06 20:51:35 +0000[diff] [blame]1062 arguments, though it is slightly weaker.
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]1063<br>
1064 For function return values, C99's <tt>restrict</tt> is not meaningful,
1065 while LLVM's <tt>noalias</tt> is.
1066 </dd>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1067
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1068 <dt><tt><b><a name="nocapture">nocapture</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1069 <dd>This indicates that the callee does not make any copies of the pointer
1070 that outlive the callee itself. This is not a valid attribute for return
1071 values.</dd>
1072
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1073 <dt><tt><b><a name="nest">nest</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1074 <dd>This indicates that the pointer parameter can be excised using the
1075 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1076 attribute for return values.</dd>
1077</dl>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1078
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1079</div>
1080
1081<!-- ======================================================================= -->
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1082<div class="doc_subsection">
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1083 <a name="gc">Garbage Collector Names</a>
1084</div>
1085
1086<div class="doc_text">
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1087
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1088<p>Each function may specify a garbage collector name, which is simply a
1089 string:</p>
1090
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1091<pre class="doc_code">
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1092define void @f() gc "name" { ... }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1093</pre>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1094
1095<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1096 collector which will cause the compiler to alter its output in order to
1097 support the named garbage collection algorithm.</p>
1098
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1099</div>
1100
1101<!-- ======================================================================= -->
1102<div class="doc_subsection">
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1103 <a name="fnattrs">Function Attributes</a>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1104</div>
1105
1106<div class="doc_text">
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1107
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1108<p>Function attributes are set to communicate additional information about a
1109 function. Function attributes are considered to be part of the function, not
1110 of the function type, so functions with different parameter attributes can
1111 have the same function type.</p>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1112
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1113<p>Function attributes are simple keywords that follow the type specified. If
1114 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1115
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1116<pre class="doc_code">
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1117define void @f() noinline { ... }
1118define void @f() alwaysinline { ... }
1119define void @f() alwaysinline optsize { ... }
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1120define void @f() optsize { ... }
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1121</pre>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1122
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1123<dl>
Charles Davisbe5557e2010-02-12 00:31:15 +0000[diff] [blame]1124 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1125 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1126 the backend should forcibly align the stack pointer. Specify the
1127 desired alignment, which must be a power of two, in parentheses.
1128
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1129 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1130 <dd>This attribute indicates that the inliner should attempt to inline this
1131 function into callers whenever possible, ignoring any active inlining size
1132 threshold for this caller.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1133
Charles Davis22fe1862010-10-25 15:37:09 +0000[diff] [blame]1134 <dt><tt><b>hotpatch</b></tt></dt>
Charles Davis1b2d3722010-10-25 16:29:03 +0000[diff] [blame]1135 <dd>This attribute indicates that the function should be 'hotpatchable',
Charles Davis74205252010-10-25 19:07:39 +0000[diff] [blame^]1136 meaning the function can be patched and/or hooked even while it is
1137 loaded into memory. On x86, the function prologue will be preceded
1138 by six bytes of padding and will begin with a two-byte instruction.
1139 Most of the functions in the Windows system DLLs in Windows XP SP2 or
1140 higher were compiled in this fashion.</dd>
Charles Davis22fe1862010-10-25 15:37:09 +0000[diff] [blame]1141
Jakob Stoklund Olesen74bb06c2010-02-06 01:16:28 +0000[diff] [blame]1142 <dt><tt><b>inlinehint</b></tt></dt>
1143 <dd>This attribute indicates that the source code contained a hint that inlining
1144 this function is desirable (such as the "inline" keyword in C/C++). It
1145 is just a hint; it imposes no requirements on the inliner.</dd>
1146
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1147 <dt><tt><b>naked</b></tt></dt>
1148 <dd>This attribute disables prologue / epilogue emission for the function.
1149 This can have very system-specific consequences.</dd>
1150
1151 <dt><tt><b>noimplicitfloat</b></tt></dt>
1152 <dd>This attributes disables implicit floating point instructions.</dd>
1153
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1154 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1155 <dd>This attribute indicates that the inliner should never inline this
1156 function in any situation. This attribute may not be used together with
1157 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1158
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1159 <dt><tt><b>noredzone</b></tt></dt>
1160 <dd>This attribute indicates that the code generator should not use a red
1161 zone, even if the target-specific ABI normally permits it.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1162
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1163 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1164 <dd>This function attribute indicates that the function never returns
1165 normally. This produces undefined behavior at runtime if the function
1166 ever does dynamically return.</dd>
Bill Wendlinga8130172008-11-13 01:02:51 +0000[diff] [blame]1167
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1168 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1169 <dd>This function attribute indicates that the function never returns with an
1170 unwind or exceptional control flow. If the function does unwind, its
1171 runtime behavior is undefined.</dd>
Bill Wendling0f5541e2008-11-26 19:07:40 +0000[diff] [blame]1172
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1173 <dt><tt><b>optsize</b></tt></dt>
1174 <dd>This attribute suggests that optimization passes and code generator passes
1175 make choices that keep the code size of this function low, and otherwise
1176 do optimizations specifically to reduce code size.</dd>
1177
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1178 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1179 <dd>This attribute indicates that the function computes its result (or decides
1180 to unwind an exception) based strictly on its arguments, without
1181 dereferencing any pointer arguments or otherwise accessing any mutable
1182 state (e.g. memory, control registers, etc) visible to caller functions.
1183 It does not write through any pointer arguments
1184 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1185 changes any state visible to callers. This means that it cannot unwind
1186 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1187 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel310fd4a2009-06-12 19:45:19 +0000[diff] [blame]1188
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1189 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1190 <dd>This attribute indicates that the function does not write through any
1191 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1192 arguments) or otherwise modify any state (e.g. memory, control registers,
1193 etc) visible to caller functions. It may dereference pointer arguments
1194 and read state that may be set in the caller. A readonly function always
1195 returns the same value (or unwinds an exception identically) when called
1196 with the same set of arguments and global state. It cannot unwind an
1197 exception by calling the <tt>C++</tt> exception throwing methods, but may
1198 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc8ce7b082009-07-17 18:07:26 +0000[diff] [blame]1199
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1200 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1201 <dd>This attribute indicates that the function should emit a stack smashing
1202 protector. It is in the form of a "canary"&mdash;a random value placed on
1203 the stack before the local variables that's checked upon return from the
1204 function to see if it has been overwritten. A heuristic is used to
1205 determine if a function needs stack protectors or not.<br>
1206<br>
1207 If a function that has an <tt>ssp</tt> attribute is inlined into a
1208 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1209 function will have an <tt>ssp</tt> attribute.</dd>
1210
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1211 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1212 <dd>This attribute indicates that the function should <em>always</em> emit a
1213 stack smashing protector. This overrides
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1214 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1215<br>
1216 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1217 function that doesn't have an <tt>sspreq</tt> attribute or which has
1218 an <tt>ssp</tt> attribute, then the resulting function will have
1219 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1220</dl>
1221
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1222</div>
1223
1224<!-- ======================================================================= -->
1225<div class="doc_subsection">
Chris Lattner93564892006-04-08 04:40:53 +0000[diff] [blame]1226 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1227</div>
1228
1229<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1230
1231<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1232 the GCC "file scope inline asm" blocks. These blocks are internally
1233 concatenated by LLVM and treated as a single unit, but may be separated in
1234 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1235
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1236<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1237module asm "inline asm code goes here"
1238module asm "more can go here"
1239</pre>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1240
1241<p>The strings can contain any character by escaping non-printable characters.
1242 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1243 for the number.</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1244
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1245<p>The inline asm code is simply printed to the machine code .s file when
1246 assembly code is generated.</p>
1247
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1248</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1249
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1250<!-- ======================================================================= -->
1251<div class="doc_subsection">
1252 <a name="datalayout">Data Layout</a>
1253</div>
1254
1255<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1256
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1257<p>A module may specify a target specific data layout string that specifies how
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1258 data is to be laid out in memory. The syntax for the data layout is
1259 simply:</p>
1260
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1261<pre class="doc_code">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1262target datalayout = "<i>layout specification</i>"
1263</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1264
1265<p>The <i>layout specification</i> consists of a list of specifications
1266 separated by the minus sign character ('-'). Each specification starts with
1267 a letter and may include other information after the letter to define some
1268 aspect of the data layout. The specifications accepted are as follows:</p>
1269
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1270<dl>
1271 <dt><tt>E</tt></dt>
1272 <dd>Specifies that the target lays out data in big-endian form. That is, the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1273 bits with the most significance have the lowest address location.</dd>
1274
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1275 <dt><tt>e</tt></dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1276 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1277 the bits with the least significance have the lowest address
1278 location.</dd>
1279
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1280 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1281 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1282 <i>preferred</i> alignments. All sizes are in bits. Specifying
1283 the <i>pref</i> alignment is optional. If omitted, the
1284 preceding <tt>:</tt> should be omitted too.</dd>
1285
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1286 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1287 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1288 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1289
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1290 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1291 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1292 <i>size</i>.</dd>
1293
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1294 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1295 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesence522852010-05-28 18:54:47 +0000[diff] [blame]1296 <i>size</i>. Only values of <i>size</i> that are supported by the target
1297 will work. 32 (float) and 64 (double) are supported on all targets;
1298 80 or 128 (different flavors of long double) are also supported on some
1299 targets.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1300
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1301 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1302 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1303 <i>size</i>.</dd>
1304
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1305 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1306 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1307 <i>size</i>.</dd>
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1308
1309 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1310 <dd>This specifies a set of native integer widths for the target CPU
1311 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1312 "n32:64" for PowerPC 64, or "n8:16:32:64" for X86-64. Elements of
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1313 this set are considered to support most general arithmetic
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1314 operations efficiently.</dd>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1315</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1316
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1317<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman61110ae2010-04-28 00:36:01 +0000[diff] [blame]1318 default set of specifications which are then (possibly) overridden by the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1319 specifications in the <tt>datalayout</tt> keyword. The default specifications
1320 are given in this list:</p>
1321
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1322<ul>
1323 <li><tt>E</tt> - big endian</li>
Dan Gohman8ad777d2010-02-23 02:44:03 +0000[diff] [blame]1324 <li><tt>p:64:64:64</tt> - 64-bit pointers with 64-bit alignment</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1325 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1326 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1327 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1328 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1329 <li><tt>i64:32:64</tt> - i64 has ABI alignment of 32-bits but preferred
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1330 alignment of 64-bits</li>
1331 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1332 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1333 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1334 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1335 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1336 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1337</ul>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1338
1339<p>When LLVM is determining the alignment for a given type, it uses the
1340 following rules:</p>
1341
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1342<ol>
1343 <li>If the type sought is an exact match for one of the specifications, that
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1344 specification is used.</li>
1345
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1346 <li>If no match is found, and the type sought is an integer type, then the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1347 smallest integer type that is larger than the bitwidth of the sought type
1348 is used. If none of the specifications are larger than the bitwidth then
1349 the the largest integer type is used. For example, given the default
1350 specifications above, the i7 type will use the alignment of i8 (next
1351 largest) while both i65 and i256 will use the alignment of i64 (largest
1352 specified).</li>
1353
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1354 <li>If no match is found, and the type sought is a vector type, then the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1355 largest vector type that is smaller than the sought vector type will be
1356 used as a fall back. This happens because &lt;128 x double&gt; can be
1357 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1358</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1359
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1360</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1361
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1362<!-- ======================================================================= -->
1363<div class="doc_subsection">
1364 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1365</div>
1366
1367<div class="doc_text">
1368
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1369<p>Any memory access must be done through a pointer value associated
Andreas Bolkae39f0332009-07-27 20:37:10 +0000[diff] [blame]1370with an address range of the memory access, otherwise the behavior
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1371is undefined. Pointer values are associated with address ranges
1372according to the following rules:</p>
1373
1374<ul>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1375 <li>A pointer value is associated with the addresses associated with
1376 any value it is <i>based</i> on.
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1377 <li>An address of a global variable is associated with the address
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1378 range of the variable's storage.</li>
1379 <li>The result value of an allocation instruction is associated with
1380 the address range of the allocated storage.</li>
1381 <li>A null pointer in the default address-space is associated with
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1382 no address.</li>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1383 <li>An integer constant other than zero or a pointer value returned
1384 from a function not defined within LLVM may be associated with address
1385 ranges allocated through mechanisms other than those provided by
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1386 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1387 allocated by mechanisms provided by LLVM.</li>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1388</ul>
1389
1390<p>A pointer value is <i>based</i> on another pointer value according
1391 to the following rules:</p>
1392
1393<ul>
1394 <li>A pointer value formed from a
1395 <tt><a href="#i_getelementptr">getelementptr</a></tt> operation
1396 is <i>based</i> on the first operand of the <tt>getelementptr</tt>.</li>
1397 <li>The result value of a
1398 <tt><a href="#i_bitcast">bitcast</a></tt> is <i>based</i> on the operand
1399 of the <tt>bitcast</tt>.</li>
1400 <li>A pointer value formed by an
1401 <tt><a href="#i_inttoptr">inttoptr</a></tt> is <i>based</i> on all
1402 pointer values that contribute (directly or indirectly) to the
1403 computation of the pointer's value.</li>
1404 <li>The "<i>based</i> on" relationship is transitive.</li>
1405</ul>
1406
1407<p>Note that this definition of <i>"based"</i> is intentionally
1408 similar to the definition of <i>"based"</i> in C99, though it is
1409 slightly weaker.</p>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1410
1411<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1412<tt><a href="#i_load">load</a></tt> merely indicates the size and
1413alignment of the memory from which to load, as well as the
Dan Gohman4eb47192010-06-17 19:23:50 +0000[diff] [blame]1414interpretation of the value. The first operand type of a
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1415<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1416and alignment of the store.</p>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1417
1418<p>Consequently, type-based alias analysis, aka TBAA, aka
1419<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1420LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1421additional information which specialized optimization passes may use
1422to implement type-based alias analysis.</p>
1423
1424</div>
1425
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1426<!-- ======================================================================= -->
1427<div class="doc_subsection">
1428 <a name="volatile">Volatile Memory Accesses</a>
1429</div>
1430
1431<div class="doc_text">
1432
1433<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1434href="#i_store"><tt>store</tt></a>s, and <a
1435href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1436The optimizers must not change the number of volatile operations or change their
1437order of execution relative to other volatile operations. The optimizers
1438<i>may</i> change the order of volatile operations relative to non-volatile
1439operations. This is not Java's "volatile" and has no cross-thread
1440synchronization behavior.</p>
1441
1442</div>
1443
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1444<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1445<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1446<!-- *********************************************************************** -->
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1447
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1448<div class="doc_text">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1449
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1450<p>The LLVM type system is one of the most important features of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1451 intermediate representation. Being typed enables a number of optimizations
1452 to be performed on the intermediate representation directly, without having
1453 to do extra analyses on the side before the transformation. A strong type
1454 system makes it easier to read the generated code and enables novel analyses
1455 and transformations that are not feasible to perform on normal three address
1456 code representations.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1457
1458</div>
1459
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1460<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1461<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1462Classifications</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1463
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1464<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1465
1466<p>The types fall into a few useful classifications:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1467
1468<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1469 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1470 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1471 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1472 <td><a href="#t_integer">integer</a></td>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1473 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1474 </tr>
1475 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1476 <td><a href="#t_floating">floating point</a></td>
1477 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1478 </tr>
1479 <tr>
1480 <td><a name="t_firstclass">first class</a></td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1481 <td><a href="#t_integer">integer</a>,
1482 <a href="#t_floating">floating point</a>,
1483 <a href="#t_pointer">pointer</a>,
Dan Gohman08783a882008-06-18 18:42:13 +0000[diff] [blame]1484 <a href="#t_vector">vector</a>,
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]1485 <a href="#t_struct">structure</a>,
1486 <a href="#t_array">array</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1487 <a href="#t_label">label</a>,
1488 <a href="#t_metadata">metadata</a>.
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1489 </td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1490 </tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1491 <tr>
1492 <td><a href="#t_primitive">primitive</a></td>
1493 <td><a href="#t_label">label</a>,
1494 <a href="#t_void">void</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1495 <a href="#t_floating">floating point</a>,
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1496 <a href="#t_x86mmx">x86mmx</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1497 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1498 </tr>
1499 <tr>
1500 <td><a href="#t_derived">derived</a></td>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1501 <td><a href="#t_array">array</a>,
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1502 <a href="#t_function">function</a>,
1503 <a href="#t_pointer">pointer</a>,
1504 <a href="#t_struct">structure</a>,
1505 <a href="#t_pstruct">packed structure</a>,
1506 <a href="#t_vector">vector</a>,
1507 <a href="#t_opaque">opaque</a>.
Dan Gohman93bf60d2008-10-14 16:32:04 +0000[diff] [blame]1508 </td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1509 </tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1510 </tbody>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1511</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1512
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1513<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1514 important. Values of these types are the only ones which can be produced by
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1515 instructions.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1516
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1517</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1518
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1519<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1520<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1521
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1522<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1523
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1524<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1525 system.</p>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1526
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1527</div>
1528
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1529<!-- _______________________________________________________________________ -->
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1530<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1531
1532<div class="doc_text">
1533
1534<h5>Overview:</h5>
1535<p>The integer type is a very simple type that simply specifies an arbitrary
1536 bit width for the integer type desired. Any bit width from 1 bit to
1537 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1538
1539<h5>Syntax:</h5>
1540<pre>
1541 iN
1542</pre>
1543
1544<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1545 value.</p>
1546
1547<h5>Examples:</h5>
1548<table class="layout">
1549 <tr class="layout">
1550 <td class="left"><tt>i1</tt></td>
1551 <td class="left">a single-bit integer.</td>
1552 </tr>
1553 <tr class="layout">
1554 <td class="left"><tt>i32</tt></td>
1555 <td class="left">a 32-bit integer.</td>
1556 </tr>
1557 <tr class="layout">
1558 <td class="left"><tt>i1942652</tt></td>
1559 <td class="left">a really big integer of over 1 million bits.</td>
1560 </tr>
1561</table>
1562
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1563</div>
1564
1565<!-- _______________________________________________________________________ -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1566<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1567
1568<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1569
1570<table>
1571 <tbody>
1572 <tr><th>Type</th><th>Description</th></tr>
1573 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1574 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1575 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1576 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1577 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1578 </tbody>
1579</table>
1580
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1581</div>
1582
1583<!-- _______________________________________________________________________ -->
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1584<div class="doc_subsubsection"> <a name="t_x86mmx">X86mmx Type</a> </div>
1585
1586<div class="doc_text">
1587
1588<h5>Overview:</h5>
1589<p>The x86mmx type represents a value held in an MMX register on an x86 machine. The operations allowed on it are quite limited: parameters and return values, load and store, and bitcast. User-specified MMX instructions are represented as intrinsic or asm calls with arguments and/or results of this type. There are no arrays, vectors or constants of this type.</p>
1590
1591<h5>Syntax:</h5>
1592<pre>
Dale Johannesenb1f0ff12010-10-01 01:07:02 +0000[diff] [blame]1593 x86mmx
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1594</pre>
1595
1596</div>
1597
1598<!-- _______________________________________________________________________ -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1599<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1600
1601<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1602
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1603<h5>Overview:</h5>
1604<p>The void type does not represent any value and has no size.</p>
1605
1606<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1607<pre>
1608 void
1609</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1610
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1611</div>
1612
1613<!-- _______________________________________________________________________ -->
1614<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1615
1616<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1617
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1618<h5>Overview:</h5>
1619<p>The label type represents code labels.</p>
1620
1621<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1622<pre>
1623 label
1624</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1625
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1626</div>
1627
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1628<!-- _______________________________________________________________________ -->
1629<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1630
1631<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1632
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1633<h5>Overview:</h5>
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]1634<p>The metadata type represents embedded metadata. No derived types may be
1635 created from metadata except for <a href="#t_function">function</a>
1636 arguments.
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1637
1638<h5>Syntax:</h5>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1639<pre>
1640 metadata
1641</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1642
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1643</div>
1644
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1645
1646<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1647<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1648
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1649<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1650
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1651<p>The real power in LLVM comes from the derived types in the system. This is
1652 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1653 useful types. Each of these types contain one or more element types which
1654 may be a primitive type, or another derived type. For example, it is
1655 possible to have a two dimensional array, using an array as the element type
1656 of another array.</p>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1657
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1658
1659</div>
1660
1661<!-- _______________________________________________________________________ -->
1662<div class="doc_subsubsection"> <a name="t_aggregate">Aggregate Types</a> </div>
1663
1664<div class="doc_text">
1665
1666<p>Aggregate Types are a subset of derived types that can contain multiple
1667 member types. <a href="#t_array">Arrays</a>,
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]1668 <a href="#t_struct">structs</a>, and <a href="#t_vector">vectors</a> are
1669 aggregate types.</p>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1670
1671</div>
1672
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1673<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1674<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1675
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1676<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1677
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1678<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1679<p>The array type is a very simple derived type that arranges elements
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1680 sequentially in memory. The array type requires a size (number of elements)
1681 and an underlying data type.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1682
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1683<h5>Syntax:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1684<pre>
1685 [&lt;# elements&gt; x &lt;elementtype&gt;]
1686</pre>
1687
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1688<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1689 be any type with a size.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1690
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1691<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1692<table class="layout">
1693 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1694 <td class="left"><tt>[40 x i32]</tt></td>
1695 <td class="left">Array of 40 32-bit integer values.</td>
1696 </tr>
1697 <tr class="layout">
1698 <td class="left"><tt>[41 x i32]</tt></td>
1699 <td class="left">Array of 41 32-bit integer values.</td>
1700 </tr>
1701 <tr class="layout">
1702 <td class="left"><tt>[4 x i8]</tt></td>
1703 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1704 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1705</table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1706<p>Here are some examples of multidimensional arrays:</p>
1707<table class="layout">
1708 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1709 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1710 <td class="left">3x4 array of 32-bit integer values.</td>
1711 </tr>
1712 <tr class="layout">
1713 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1714 <td class="left">12x10 array of single precision floating point values.</td>
1715 </tr>
1716 <tr class="layout">
1717 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1718 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1719 </tr>
1720</table>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1721
Dan Gohmanc74bc282009-11-09 19:01:53 +0000[diff] [blame]1722<p>There is no restriction on indexing beyond the end of the array implied by
1723 a static type (though there are restrictions on indexing beyond the bounds
1724 of an allocated object in some cases). This means that single-dimension
1725 'variable sized array' addressing can be implemented in LLVM with a zero
1726 length array type. An implementation of 'pascal style arrays' in LLVM could
1727 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1728
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1729</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1730
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1731<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1732<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1733
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1734<div class="doc_text">
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1735
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1736<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1737<p>The function type can be thought of as a function signature. It consists of
1738 a return type and a list of formal parameter types. The return type of a
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]1739 function type is a first class type or a void type.</p>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1740
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1741<h5>Syntax:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1742<pre>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]1743 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1744</pre>
1745
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1746<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1747 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1748 which indicates that the function takes a variable number of arguments.
1749 Variable argument functions can access their arguments with
1750 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]1751 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]1752 <a href="#t_label">label</a>.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1753
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1754<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1755<table class="layout">
1756 <tr class="layout">
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1757 <td class="left"><tt>i32 (i32)</tt></td>
1758 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1759 </td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1760 </tr><tr class="layout">
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]1761 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencer655dcc62006-12-31 07:20:23 +0000[diff] [blame]1762 </tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1763 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]1764 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
1765 returning <tt>float</tt>.
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1766 </td>
1767 </tr><tr class="layout">
1768 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1769 <td class="left">A vararg function that takes at least one
1770 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1771 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1772 LLVM.
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1773 </td>
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]1774 </tr><tr class="layout">
1775 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]1776 <td class="left">A function taking an <tt>i32</tt>, returning a
1777 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]1778 </td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1779 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1780</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1781
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1782</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1783
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1784<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1785<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1786
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1787<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1788
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1789<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1790<p>The structure type is used to represent a collection of data members together
1791 in memory. The packing of the field types is defined to match the ABI of the
1792 underlying processor. The elements of a structure may be any type that has a
1793 size.</p>
1794
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]1795<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
1796 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
1797 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1798 Structures in registers are accessed using the
1799 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
1800 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1801<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1802<pre>
1803 { &lt;type list&gt; }
1804</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1805
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1806<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1807<table class="layout">
1808 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1809 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1810 <td class="left">A triple of three <tt>i32</tt> values</td>
1811 </tr><tr class="layout">
1812 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1813 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1814 second element is a <a href="#t_pointer">pointer</a> to a
1815 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1816 an <tt>i32</tt>.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1817 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1818</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1819
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1820</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1821
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1822<!-- _______________________________________________________________________ -->
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1823<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1824</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1825
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1826<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1827
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1828<h5>Overview:</h5>
1829<p>The packed structure type is used to represent a collection of data members
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1830 together in memory. There is no padding between fields. Further, the
1831 alignment of a packed structure is 1 byte. The elements of a packed
1832 structure may be any type that has a size.</p>
1833
1834<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1835 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1836 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1837
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1838<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1839<pre>
1840 &lt; { &lt;type list&gt; } &gt;
1841</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1842
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1843<h5>Examples:</h5>
1844<table class="layout">
1845 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1846 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1847 <td class="left">A triple of three <tt>i32</tt> values</td>
1848 </tr><tr class="layout">
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1849 <td class="left">
1850<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1851 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1852 second element is a <a href="#t_pointer">pointer</a> to a
1853 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1854 an <tt>i32</tt>.</td>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1855 </tr>
1856</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1857
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1858</div>
1859
1860<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1861<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]1862
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1863<div class="doc_text">
1864
1865<h5>Overview:</h5>
Dan Gohman88481112010-02-25 16:50:07 +0000[diff] [blame]1866<p>The pointer type is used to specify memory locations.
1867 Pointers are commonly used to reference objects in memory.</p>
1868
1869<p>Pointer types may have an optional address space attribute defining the
1870 numbered address space where the pointed-to object resides. The default
1871 address space is number zero. The semantics of non-zero address
1872 spaces are target-specific.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1873
1874<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1875 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]1876
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1877<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1878<pre>
1879 &lt;type&gt; *
1880</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1881
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1882<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1883<table class="layout">
1884 <tr class="layout">
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]1885 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1886 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1887 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1888 </tr>
1889 <tr class="layout">
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]1890 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1891 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1892 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1893 <tt>i32</tt>.</td>
1894 </tr>
1895 <tr class="layout">
1896 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1897 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1898 that resides in address space #5.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1899 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1900</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1901
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1902</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1903
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1904<!-- _______________________________________________________________________ -->
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1905<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1906
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1907<div class="doc_text">
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1908
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1909<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1910<p>A vector type is a simple derived type that represents a vector of elements.
1911 Vector types are used when multiple primitive data are operated in parallel
1912 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sands31c0e0e2009-11-27 13:38:03 +0000[diff] [blame]1913 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1914 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1915
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1916<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1917<pre>
1918 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1919</pre>
1920
Chris Lattnerf11031a2010-10-10 18:20:35 +0000[diff] [blame]1921<p>The number of elements is a constant integer value larger than 0; elementtype
1922 may be any integer or floating point type. Vectors of size zero are not
1923 allowed, and pointers are not allowed as the element type.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1924
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1925<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1926<table class="layout">
1927 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1928 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1929 <td class="left">Vector of 4 32-bit integer values.</td>
1930 </tr>
1931 <tr class="layout">
1932 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1933 <td class="left">Vector of 8 32-bit floating-point values.</td>
1934 </tr>
1935 <tr class="layout">
1936 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1937 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1938 </tr>
1939</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1940
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1941</div>
1942
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1943<!-- _______________________________________________________________________ -->
1944<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1945<div class="doc_text">
1946
1947<h5>Overview:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1948<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1949 corresponds (for example) to the C notion of a forward declared structure
1950 type. In LLVM, opaque types can eventually be resolved to any type (not just
1951 a structure type).</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1952
1953<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1954<pre>
1955 opaque
1956</pre>
1957
1958<h5>Examples:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1959<table class="layout">
1960 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1961 <td class="left"><tt>opaque</tt></td>
1962 <td class="left">An opaque type.</td>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1963 </tr>
1964</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1965
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1966</div>
1967
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1968<!-- ======================================================================= -->
1969<div class="doc_subsection">
1970 <a name="t_uprefs">Type Up-references</a>
1971</div>
1972
1973<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1974
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1975<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1976<p>An "up reference" allows you to refer to a lexically enclosing type without
1977 requiring it to have a name. For instance, a structure declaration may
1978 contain a pointer to any of the types it is lexically a member of. Example
1979 of up references (with their equivalent as named type declarations)
1980 include:</p>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1981
1982<pre>
Chris Lattnerbf1d5452009-02-09 10:00:56 +0000[diff] [blame]1983 { \2 * } %x = type { %x* }
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1984 { \2 }* %y = type { %y }*
1985 \1* %z = type %z*
1986</pre>
1987
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1988<p>An up reference is needed by the asmprinter for printing out cyclic types
1989 when there is no declared name for a type in the cycle. Because the
1990 asmprinter does not want to print out an infinite type string, it needs a
1991 syntax to handle recursive types that have no names (all names are optional
1992 in llvm IR).</p>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1993
1994<h5>Syntax:</h5>
1995<pre>
1996 \&lt;level&gt;
1997</pre>
1998
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1999<p>The level is the count of the lexical type that is being referred to.</p>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]2000
2001<h5>Examples:</h5>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]2002<table class="layout">
2003 <tr class="layout">
2004 <td class="left"><tt>\1*</tt></td>
2005 <td class="left">Self-referential pointer.</td>
2006 </tr>
2007 <tr class="layout">
2008 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
2009 <td class="left">Recursive structure where the upref refers to the out-most
2010 structure.</td>
2011 </tr>
2012</table>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]2013
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2014</div>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2015
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2016<!-- *********************************************************************** -->
2017<div class="doc_section"> <a name="constants">Constants</a> </div>
2018<!-- *********************************************************************** -->
2019
2020<div class="doc_text">
2021
2022<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2023 them all and their syntax.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2024
2025</div>
2026
2027<!-- ======================================================================= -->
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]2028<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2029
2030<div class="doc_text">
2031
2032<dl>
2033 <dt><b>Boolean constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2034 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]2035 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2036
2037 <dt><b>Integer constants</b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2038 <dd>Standard integers (such as '4') are constants of
2039 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2040 with integer types.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2041
2042 <dt><b>Floating point constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2043 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2044 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2045 notation (see below). The assembler requires the exact decimal value of a
2046 floating-point constant. For example, the assembler accepts 1.25 but
2047 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2048 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2049
2050 <dt><b>Null pointer constants</b></dt>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2051 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2052 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2053</dl>
2054
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2055<p>The one non-intuitive notation for constants is the hexadecimal form of
2056 floating point constants. For example, the form '<tt>double
2057 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2058 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2059 constants are required (and the only time that they are generated by the
2060 disassembler) is when a floating point constant must be emitted but it cannot
2061 be represented as a decimal floating point number in a reasonable number of
2062 digits. For example, NaN's, infinities, and other special values are
2063 represented in their IEEE hexadecimal format so that assembly and disassembly
2064 do not cause any bits to change in the constants.</p>
2065
Dale Johannesencd4a3012009-02-11 22:14:51 +0000[diff] [blame]2066<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2067 represented using the 16-digit form shown above (which matches the IEEE754
2068 representation for double); float values must, however, be exactly
2069 representable as IEE754 single precision. Hexadecimal format is always used
2070 for long double, and there are three forms of long double. The 80-bit format
2071 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2072 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2073 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2074 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2075 currently supported target uses this format. Long doubles will only work if
2076 they match the long double format on your target. All hexadecimal formats
2077 are big-endian (sign bit at the left).</p>
2078
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]2079<p>There are no constants of type x86mmx.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2080</div>
2081
2082<!-- ======================================================================= -->
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]2083<div class="doc_subsection">
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]2084<a name="aggregateconstants"></a> <!-- old anchor -->
2085<a name="complexconstants">Complex Constants</a>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2086</div>
2087
2088<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2089
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]2090<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2091 constants and smaller complex constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2092
2093<dl>
2094 <dt><b>Structure constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2095 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2096 type definitions (a comma separated list of elements, surrounded by braces
2097 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2098 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2099 Structure constants must have <a href="#t_struct">structure type</a>, and
2100 the number and types of elements must match those specified by the
2101 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2102
2103 <dt><b>Array constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2104 <dd>Array constants are represented with notation similar to array type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2105 definitions (a comma separated list of elements, surrounded by square
2106 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2107 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2108 the number and types of elements must match those specified by the
2109 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2110
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2111 <dt><b>Vector constants</b></dt>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2112 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2113 definitions (a comma separated list of elements, surrounded by
2114 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2115 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2116 have <a href="#t_vector">vector type</a>, and the number and types of
2117 elements must match those specified by the type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2118
2119 <dt><b>Zero initialization</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2120 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]2121 value to zero of <em>any</em> type, including scalar and
2122 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2123 This is often used to avoid having to print large zero initializers
2124 (e.g. for large arrays) and is always exactly equivalent to using explicit
2125 zero initializers.</dd>
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]2126
2127 <dt><b>Metadata node</b></dt>
Nick Lewycky8e2c4f42009-05-30 16:08:30 +0000[diff] [blame]2128 <dd>A metadata node is a structure-like constant with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2129 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2130 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2131 be interpreted as part of the instruction stream, metadata is a place to
2132 attach additional information such as debug info.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2133</dl>
2134
2135</div>
2136
2137<!-- ======================================================================= -->
2138<div class="doc_subsection">
2139 <a name="globalconstants">Global Variable and Function Addresses</a>
2140</div>
2141
2142<div class="doc_text">
2143
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2144<p>The addresses of <a href="#globalvars">global variables</a>
2145 and <a href="#functionstructure">functions</a> are always implicitly valid
2146 (link-time) constants. These constants are explicitly referenced when
2147 the <a href="#identifiers">identifier for the global</a> is used and always
2148 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2149 legal LLVM file:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2150
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2151<pre class="doc_code">
Chris Lattner00538a12007-06-06 18:28:13 +0000[diff] [blame]2152@X = global i32 17
2153@Y = global i32 42
2154@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2155</pre>
2156
2157</div>
2158
2159<!-- ======================================================================= -->
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]2160<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2161<div class="doc_text">
2162
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2163<p>The string '<tt>undef</tt>' can be used anywhere a constant is expected, and
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]2164 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2165 Undefined values may be of any type (other than label or void) and be used
2166 anywhere a constant is permitted.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2167
Chris Lattner92ada5d2009-09-11 01:49:31 +0000[diff] [blame]2168<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2169 program is well defined no matter what value is used. This gives the
2170 compiler more freedom to optimize. Here are some examples of (potentially
2171 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2172
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2173
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2174<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2175 %A = add %X, undef
2176 %B = sub %X, undef
2177 %C = xor %X, undef
2178Safe:
2179 %A = undef
2180 %B = undef
2181 %C = undef
2182</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2183
2184<p>This is safe because all of the output bits are affected by the undef bits.
2185Any output bit can have a zero or one depending on the input bits.</p>
2186
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2187<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2188 %A = or %X, undef
2189 %B = and %X, undef
2190Safe:
2191 %A = -1
2192 %B = 0
2193Unsafe:
2194 %A = undef
2195 %B = undef
2196</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2197
2198<p>These logical operations have bits that are not always affected by the input.
2199For example, if "%X" has a zero bit, then the output of the 'and' operation will
2200always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattner92ada5d2009-09-11 01:49:31 +0000[diff] [blame]2201such, it is unsafe to optimize or assume that the result of the and is undef.
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2202However, it is safe to assume that all bits of the undef could be 0, and
2203optimize the and to 0. Likewise, it is safe to assume that all the bits of
2204the undef operand to the or could be set, allowing the or to be folded to
Chris Lattner92ada5d2009-09-11 01:49:31 +0000[diff] [blame]2205-1.</p>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2206
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2207<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2208 %A = select undef, %X, %Y
2209 %B = select undef, 42, %Y
2210 %C = select %X, %Y, undef
2211Safe:
2212 %A = %X (or %Y)
2213 %B = 42 (or %Y)
2214 %C = %Y
2215Unsafe:
2216 %A = undef
2217 %B = undef
2218 %C = undef
2219</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2220
2221<p>This set of examples show that undefined select (and conditional branch)
2222conditions can go "either way" but they have to come from one of the two
2223operands. In the %A example, if %X and %Y were both known to have a clear low
2224bit, then %A would have to have a cleared low bit. However, in the %C example,
2225the optimizer is allowed to assume that the undef operand could be the same as
2226%Y, allowing the whole select to be eliminated.</p>
2227
2228
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2229<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2230 %A = xor undef, undef
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2231
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2232 %B = undef
2233 %C = xor %B, %B
2234
2235 %D = undef
2236 %E = icmp lt %D, 4
2237 %F = icmp gte %D, 4
2238
2239Safe:
2240 %A = undef
2241 %B = undef
2242 %C = undef
2243 %D = undef
2244 %E = undef
2245 %F = undef
2246</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2247
2248<p>This example points out that two undef operands are not necessarily the same.
2249This can be surprising to people (and also matches C semantics) where they
2250assume that "X^X" is always zero, even if X is undef. This isn't true for a
2251number of reasons, but the short answer is that an undef "variable" can
2252arbitrarily change its value over its "live range". This is true because the
2253"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2254logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]2255so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattner6760e542009-09-08 15:13:16 +0000[diff] [blame]2256to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2257would not hold.</p>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2258
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2259<pre class="doc_code">
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2260 %A = fdiv undef, %X
2261 %B = fdiv %X, undef
2262Safe:
2263 %A = undef
2264b: unreachable
2265</pre>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2266
2267<p>These examples show the crucial difference between an <em>undefined
2268value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2269allowed to have an arbitrary bit-pattern. This means that the %A operation
2270can be constant folded to undef because the undef could be an SNaN, and fdiv is
2271not (currently) defined on SNaN's. However, in the second example, we can make
2272a more aggressive assumption: because the undef is allowed to be an arbitrary
2273value, we are allowed to assume that it could be zero. Since a divide by zero
Chris Lattner10ff0c12009-09-08 19:45:34 +0000[diff] [blame]2274has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2275does not execute at all. This allows us to delete the divide and all code after
2276it: since the undefined operation "can't happen", the optimizer can assume that
2277it occurs in dead code.
2278</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2279
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2280<pre class="doc_code">
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2281a: store undef -> %X
2282b: store %X -> undef
2283Safe:
2284a: &lt;deleted&gt;
2285b: unreachable
2286</pre>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2287
2288<p>These examples reiterate the fdiv example: a store "of" an undefined value
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2289can be assumed to not have any effect: we can assume that the value is
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2290overwritten with bits that happen to match what was already there. However, a
2291store "to" an undefined location could clobber arbitrary memory, therefore, it
2292has undefined behavior.</p>
2293
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2294</div>
2295
2296<!-- ======================================================================= -->
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2297<div class="doc_subsection"><a name="trapvalues">Trap Values</a></div>
2298<div class="doc_text">
2299
Dan Gohmanb2a709b2010-04-26 20:21:21 +0000[diff] [blame]2300<p>Trap values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2301 instead of representing an unspecified bit pattern, they represent the
2302 fact that an instruction or constant expression which cannot evoke side
2303 effects has nevertheless detected a condition which results in undefined
Dan Gohmanb2a709b2010-04-26 20:21:21 +0000[diff] [blame]2304 behavior.</p>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2305
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2306<p>There is currently no way of representing a trap value in the IR; they
Dan Gohmanac355aa2010-05-03 14:51:43 +0000[diff] [blame]2307 only exist when produced by operations such as
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2308 <a href="#i_add"><tt>add</tt></a> with the <tt>nsw</tt> flag.</p>
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2309
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2310<p>Trap value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2311
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2312<ul>
2313<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2314 their operands.</li>
2315
2316<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2317 to their dynamic predecessor basic block.</li>
2318
2319<li>Function arguments depend on the corresponding actual argument values in
2320 the dynamic callers of their functions.</li>
2321
2322<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2323 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2324 control back to them.</li>
2325
Dan Gohman7292a752010-05-03 14:55:22 +0000[diff] [blame]2326<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
2327 <a href="#i_ret"><tt>ret</tt></a>, <a href="#i_unwind"><tt>unwind</tt></a>,
2328 or exception-throwing call instructions that dynamically transfer control
2329 back to them.</li>
2330
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2331<li>Non-volatile loads and stores depend on the most recent stores to all of the
2332 referenced memory addresses, following the order in the IR
2333 (including loads and stores implied by intrinsics such as
2334 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2335
Dan Gohman3513ea52010-05-03 14:59:34 +0000[diff] [blame]2336<!-- TODO: In the case of multiple threads, this only applies if the store
2337 "happens-before" the load or store. -->
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2338
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2339<!-- TODO: floating-point exception state -->
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2340
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2341<li>An instruction with externally visible side effects depends on the most
2342 recent preceding instruction with externally visible side effects, following
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]2343 the order in the IR. (This includes
2344 <a href="#volatile">volatile operations</a>.)</li>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2345
Dan Gohman7292a752010-05-03 14:55:22 +0000[diff] [blame]2346<li>An instruction <i>control-depends</i> on a
2347 <a href="#terminators">terminator instruction</a>
2348 if the terminator instruction has multiple successors and the instruction
2349 is always executed when control transfers to one of the successors, and
2350 may not be executed when control is transfered to another.</li>
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2351
2352<li>Dependence is transitive.</li>
2353
2354</ul>
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2355
2356<p>Whenever a trap value is generated, all values which depend on it evaluate
2357 to trap. If they have side effects, the evoke their side effects as if each
2358 operand with a trap value were undef. If they have externally-visible side
2359 effects, the behavior is undefined.</p>
2360
2361<p>Here are some examples:</p>
Dan Gohman48a25882010-04-26 20:54:53 +0000[diff] [blame]2362
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2363<pre class="doc_code">
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2364entry:
2365 %trap = sub nuw i32 0, 1 ; Results in a trap value.
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2366 %still_trap = and i32 %trap, 0 ; Whereas (and i32 undef, 0) would return 0.
2367 %trap_yet_again = getelementptr i32* @h, i32 %still_trap
2368 store i32 0, i32* %trap_yet_again ; undefined behavior
2369
2370 store i32 %trap, i32* @g ; Trap value conceptually stored to memory.
2371 %trap2 = load i32* @g ; Returns a trap value, not just undef.
2372
2373 volatile store i32 %trap, i32* @g ; External observation; undefined behavior.
2374
2375 %narrowaddr = bitcast i32* @g to i16*
2376 %wideaddr = bitcast i32* @g to i64*
2377 %trap3 = load 16* %narrowaddr ; Returns a trap value.
2378 %trap4 = load i64* %widaddr ; Returns a trap value.
2379
2380 %cmp = icmp i32 slt %trap, 0 ; Returns a trap value.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2381 %br i1 %cmp, %true, %end ; Branch to either destination.
2382
2383true:
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2384 volatile store i32 0, i32* @g ; This is control-dependent on %cmp, so
2385 ; it has undefined behavior.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2386 br label %end
2387
2388end:
2389 %p = phi i32 [ 0, %entry ], [ 1, %true ]
2390 ; Both edges into this PHI are
2391 ; control-dependent on %cmp, so this
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2392 ; always results in a trap value.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2393
2394 volatile store i32 0, i32* @g ; %end is control-equivalent to %entry
2395 ; so this is defined (ignoring earlier
2396 ; undefined behavior in this example).
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2397</pre>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2398
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2399</div>
2400
2401<!-- ======================================================================= -->
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]2402<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2403 Blocks</a></div>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2404<div class="doc_text">
2405
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2406<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2407
2408<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner5c5f0ac2009-10-27 21:49:40 +0000[diff] [blame]2409 basic block in the specified function, and always has an i8* type. Taking
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2410 the address of the entry block is illegal.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2411
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2412<p>This value only has defined behavior when used as an operand to the
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2413 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction or for comparisons
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2414 against null. Pointer equality tests between labels addresses is undefined
2415 behavior - though, again, comparison against null is ok, and no label is
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]2416 equal to the null pointer. This may also be passed around as an opaque
2417 pointer sized value as long as the bits are not inspected. This allows
Chris Lattnerda37b302009-10-27 21:44:20 +0000[diff] [blame]2418 <tt>ptrtoint</tt> and arithmetic to be performed on these values so long as
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2419 the original value is reconstituted before the <tt>indirectbr</tt>.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2420
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]2421<p>Finally, some targets may provide defined semantics when
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2422 using the value as the operand to an inline assembly, but that is target
2423 specific.
2424 </p>
2425
2426</div>
2427
2428
2429<!-- ======================================================================= -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2430<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2431</div>
2432
2433<div class="doc_text">
2434
2435<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2436 to be used as constants. Constant expressions may be of
2437 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2438 operation that does not have side effects (e.g. load and call are not
2439 supported). The following is the syntax for constant expressions:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2440
2441<dl>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2442 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2443 <dd>Truncate a constant to another type. The bit size of CST must be larger
2444 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2445
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2446 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2447 <dd>Zero extend a constant to another type. The bit size of CST must be
Duncan Sandsa522e562010-07-13 12:06:14 +0000[diff] [blame]2448 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2449
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2450 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2451 <dd>Sign extend a constant to another type. The bit size of CST must be
Duncan Sandsa522e562010-07-13 12:06:14 +0000[diff] [blame]2452 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2453
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2454 <dt><b><tt>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2455 <dd>Truncate a floating point constant to another floating point type. The
2456 size of CST must be larger than the size of TYPE. Both types must be
2457 floating point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2458
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2459 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2460 <dd>Floating point extend a constant to another type. The size of CST must be
2461 smaller or equal to the size of TYPE. Both types must be floating
2462 point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2463
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2464 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2465 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2466 constant. TYPE must be a scalar or vector integer type. CST must be of
2467 scalar or vector floating point type. Both CST and TYPE must be scalars,
2468 or vectors of the same number of elements. If the value won't fit in the
2469 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2470
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2471 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2472 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2473 constant. TYPE must be a scalar or vector integer type. CST must be of
2474 scalar or vector floating point type. Both CST and TYPE must be scalars,
2475 or vectors of the same number of elements. If the value won't fit in the
2476 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2477
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2478 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2479 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2480 constant. TYPE must be a scalar or vector floating point type. CST must be
2481 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2482 vectors of the same number of elements. If the value won't fit in the
2483 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2484
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2485 <dt><b><tt>sitofp (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2486 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2487 constant. TYPE must be a scalar or vector floating point type. CST must be
2488 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2489 vectors of the same number of elements. If the value won't fit in the
2490 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2491
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2492 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2493 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2494 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2495 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2496 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2497
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2498 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2499 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2500 type. CST must be of integer type. The CST value is zero extended,
2501 truncated, or unchanged to make it fit in a pointer size. This one is
2502 <i>really</i> dangerous!</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2503
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2504 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner789dee32009-02-28 18:27:03 +0000[diff] [blame]2505 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2506 are the same as those for the <a href="#i_bitcast">bitcast
2507 instruction</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2508
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2509 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2510 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2511 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2512 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2513 instruction, the index list may have zero or more indexes, which are
2514 required to make sense for the type of "CSTPTR".</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2515
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2516 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2517 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2518
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2519 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2520 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2521
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2522 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2523 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2524
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2525 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2526 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2527 constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2528
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2529 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2530 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2531 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2532
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2533 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2534 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2535 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2536
Nick Lewycky9ab9a7f2010-05-29 06:44:15 +0000[diff] [blame]2537 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2538 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2539 constants. The index list is interpreted in a similar manner as indices in
2540 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2541 index value must be specified.</dd>
2542
2543 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2544 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2545 constants. The index list is interpreted in a similar manner as indices in
2546 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2547 index value must be specified.</dd>
2548
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2549 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2550 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2551 be any of the <a href="#binaryops">binary</a>
2552 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2553 on operands are the same as those for the corresponding instruction
2554 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2555</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2556
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2557</div>
Chris Lattnerb1652612004-03-08 16:49:10 +0000[diff] [blame]2558
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2559<!-- *********************************************************************** -->
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2560<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2561<!-- *********************************************************************** -->
2562
2563<!-- ======================================================================= -->
2564<div class="doc_subsection">
2565<a name="inlineasm">Inline Assembler Expressions</a>
2566</div>
2567
2568<div class="doc_text">
2569
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2570<p>LLVM supports inline assembler expressions (as opposed
2571 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2572 a special value. This value represents the inline assembler as a string
2573 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2574 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2575 expression has side effects, and a flag indicating whether the function
2576 containing the asm needs to align its stack conservatively. An example
2577 inline assembler expression is:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2578
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2579<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2580i32 (i32) asm "bswap $0", "=r,r"
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2581</pre>
2582
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2583<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2584 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2585 have:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2586
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2587<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2588%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2589</pre>
2590
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2591<p>Inline asms with side effects not visible in the constraint list must be
2592 marked as having side effects. This is done through the use of the
2593 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2594
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2595<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2596call void asm sideeffect "eieio", ""()
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2597</pre>
2598
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2599<p>In some cases inline asms will contain code that will not work unless the
2600 stack is aligned in some way, such as calls or SSE instructions on x86,
2601 yet will not contain code that does that alignment within the asm.
2602 The compiler should make conservative assumptions about what the asm might
2603 contain and should generate its usual stack alignment code in the prologue
2604 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2605
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2606<pre class="doc_code">
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2607call void asm alignstack "eieio", ""()
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2608</pre>
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2609
2610<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2611 first.</p>
2612
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2613<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2614 documented here. Constraints on what can be done (e.g. duplication, moving,
2615 etc need to be documented). This is probably best done by reference to
2616 another document that covers inline asm from a holistic perspective.</p>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2617</div>
2618
2619<div class="doc_subsubsection">
2620<a name="inlineasm_md">Inline Asm Metadata</a>
2621</div>
2622
2623<div class="doc_text">
2624
2625<p>The call instructions that wrap inline asm nodes may have a "!srcloc" MDNode
2626 attached to it that contains a constant integer. If present, the code
2627 generator will use the integer as the location cookie value when report
2628 errors through the LLVMContext error reporting mechanisms. This allows a
Dan Gohman61110ae2010-04-28 00:36:01 +0000[diff] [blame]2629 front-end to correlate backend errors that occur with inline asm back to the
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2630 source code that produced it. For example:</p>
2631
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2632<pre class="doc_code">
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2633call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2634...
2635!42 = !{ i32 1234567 }
2636</pre>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2637
2638<p>It is up to the front-end to make sense of the magic numbers it places in the
2639 IR.</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2640
2641</div>
2642
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2643<!-- ======================================================================= -->
2644<div class="doc_subsection"><a name="metadata">Metadata Nodes and Metadata
2645 Strings</a>
2646</div>
2647
2648<div class="doc_text">
2649
2650<p>LLVM IR allows metadata to be attached to instructions in the program that
2651 can convey extra information about the code to the optimizers and code
2652 generator. One example application of metadata is source-level debug
2653 information. There are two metadata primitives: strings and nodes. All
2654 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2655 preceding exclamation point ('<tt>!</tt>').</p>
2656
2657<p>A metadata string is a string surrounded by double quotes. It can contain
2658 any character by escaping non-printable characters with "\xx" where "xx" is
2659 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2660
2661<p>Metadata nodes are represented with notation similar to structure constants
2662 (a comma separated list of elements, surrounded by braces and preceded by an
2663 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2664 10}</tt>". Metadata nodes can have any values as their operand.</p>
2665
2666<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2667 metadata nodes, which can be looked up in the module symbol table. For
2668 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2669
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2670<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2671 function is using two metadata arguments.</p>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2672
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2673 <pre class="doc_code">
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2674 call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2675 </pre>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2676
2677<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2678 attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.</p>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2679
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2680 <pre class="doc_code">
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2681 %indvar.next = add i64 %indvar, 1, !dbg !21
2682 </pre>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2683</div>
2684
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2685
2686<!-- *********************************************************************** -->
2687<div class="doc_section">
2688 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2689</div>
2690<!-- *********************************************************************** -->
2691
2692<p>LLVM has a number of "magic" global variables that contain data that affect
2693code generation or other IR semantics. These are documented here. All globals
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]2694of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2695section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2696by LLVM.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2697
2698<!-- ======================================================================= -->
2699<div class="doc_subsection">
2700<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2701</div>
2702
2703<div class="doc_text">
2704
2705<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2706href="#linkage_appending">appending linkage</a>. This array contains a list of
2707pointers to global variables and functions which may optionally have a pointer
2708cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2709
2710<pre>
2711 @X = global i8 4
2712 @Y = global i32 123
2713
2714 @llvm.used = appending global [2 x i8*] [
2715 i8* @X,
2716 i8* bitcast (i32* @Y to i8*)
2717 ], section "llvm.metadata"
2718</pre>
2719
2720<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2721compiler, assembler, and linker are required to treat the symbol as if there is
2722a reference to the global that it cannot see. For example, if a variable has
2723internal linkage and no references other than that from the <tt>@llvm.used</tt>
2724list, it cannot be deleted. This is commonly used to represent references from
2725inline asms and other things the compiler cannot "see", and corresponds to
2726"attribute((used))" in GNU C.</p>
2727
2728<p>On some targets, the code generator must emit a directive to the assembler or
2729object file to prevent the assembler and linker from molesting the symbol.</p>
2730
2731</div>
2732
2733<!-- ======================================================================= -->
2734<div class="doc_subsection">
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]2735<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2736</div>
2737
2738<div class="doc_text">
2739
2740<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2741<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2742touching the symbol. On targets that support it, this allows an intelligent
2743linker to optimize references to the symbol without being impeded as it would be
2744by <tt>@llvm.used</tt>.</p>
2745
2746<p>This is a rare construct that should only be used in rare circumstances, and
2747should not be exposed to source languages.</p>
2748
2749</div>
2750
2751<!-- ======================================================================= -->
2752<div class="doc_subsection">
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2753<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2754</div>
2755
2756<div class="doc_text">
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2757<pre>
2758%0 = type { i32, void ()* }
David Chisnallb492b812010-04-30 19:27:35 +0000[diff] [blame]2759@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2760</pre>
2761<p>The <tt>@llvm.global_ctors</tt> array contains a list of constructor functions and associated priorities. The functions referenced by this array will be called in ascending order of priority (i.e. lowest first) when the module is loaded. The order of functions with the same priority is not defined.
2762</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2763
2764</div>
2765
2766<!-- ======================================================================= -->
2767<div class="doc_subsection">
2768<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2769</div>
2770
2771<div class="doc_text">
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2772<pre>
2773%0 = type { i32, void ()* }
David Chisnallb492b812010-04-30 19:27:35 +0000[diff] [blame]2774@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2775</pre>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2776
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]2777<p>The <tt>@llvm.global_dtors</tt> array contains a list of destructor functions and associated priorities. The functions referenced by this array will be called in descending order of priority (i.e. highest first) when the module is loaded. The order of functions with the same priority is not defined.
2778</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2779
2780</div>
2781
2782
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2783<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2784<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2785<!-- *********************************************************************** -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2786
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2787<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2788
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2789<p>The LLVM instruction set consists of several different classifications of
2790 instructions: <a href="#terminators">terminator
2791 instructions</a>, <a href="#binaryops">binary instructions</a>,
2792 <a href="#bitwiseops">bitwise binary instructions</a>,
2793 <a href="#memoryops">memory instructions</a>, and
2794 <a href="#otherops">other instructions</a>.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2795
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2796</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2797
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2798<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2799<div class="doc_subsection"> <a name="terminators">Terminator
2800Instructions</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2801
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2802<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2803
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2804<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2805 in a program ends with a "Terminator" instruction, which indicates which
2806 block should be executed after the current block is finished. These
2807 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2808 control flow, not values (the one exception being the
2809 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2810
Duncan Sands626b0242010-04-15 20:35:54 +0000[diff] [blame]2811<p>There are seven different terminator instructions: the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2812 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2813 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2814 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendling33fef7e2009-11-02 00:25:26 +0000[diff] [blame]2815 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2816 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2817 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2818 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2819
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2820</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2821
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2822<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2823<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2824Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2825
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2826<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2827
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2828<h5>Syntax:</h5>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]2829<pre>
2830 ret &lt;type&gt; &lt;value&gt; <i>; Return a value from a non-void function</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2831 ret void <i>; Return from void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2832</pre>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2833
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2834<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2835<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2836 a value) from a function back to the caller.</p>
2837
2838<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2839 value and then causes control flow, and one that just causes control flow to
2840 occur.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2841
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2842<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2843<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2844 return value. The type of the return value must be a
2845 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]2846
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2847<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2848 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2849 value or a return value with a type that does not match its type, or if it
2850 has a void return type and contains a '<tt>ret</tt>' instruction with a
2851 return value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2852
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2853<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2854<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2855 the calling function's context. If the caller is a
2856 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2857 instruction after the call. If the caller was an
2858 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2859 the beginning of the "normal" destination block. If the instruction returns
2860 a value, that value shall set the call or invoke instruction's return
2861 value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2862
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2863<h5>Example:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2864<pre>
2865 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2866 ret void <i>; Return from a void function</i>
Bill Wendling050ee8f2009-02-28 22:12:54 +0000[diff] [blame]2867 ret { i32, i8 } { i32 4, i8 2 } <i>; Return a struct of values 4 and 2</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2868</pre>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]2869
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2870</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2871<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2872<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2873
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2874<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2875
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2876<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2877<pre>
2878 br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;<br> br label &lt;dest&gt; <i>; Unconditional branch</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2879</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2880
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2881<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2882<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2883 different basic block in the current function. There are two forms of this
2884 instruction, corresponding to a conditional branch and an unconditional
2885 branch.</p>
2886
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2887<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2888<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2889 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2890 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2891 target.</p>
2892
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2893<h5>Semantics:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2894<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2895 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2896 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2897 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2898
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2899<h5>Example:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2900<pre>
2901Test:
2902 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2903 br i1 %cond, label %IfEqual, label %IfUnequal
2904IfEqual:
2905 <a href="#i_ret">ret</a> i32 1
2906IfUnequal:
2907 <a href="#i_ret">ret</a> i32 0
2908</pre>
2909
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2910</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2911
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2912<!-- _______________________________________________________________________ -->
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2913<div class="doc_subsubsection">
2914 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2915</div>
2916
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2917<div class="doc_text">
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2918
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2919<h5>Syntax:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2920<pre>
2921 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2922</pre>
2923
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2924<h5>Overview:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2925<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2926 several different places. It is a generalization of the '<tt>br</tt>'
2927 instruction, allowing a branch to occur to one of many possible
2928 destinations.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2929
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2930<h5>Arguments:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2931<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2932 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2933 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2934 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2935
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2936<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2937<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2938 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2939 is searched for the given value. If the value is found, control flow is
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]2940 transferred to the corresponding destination; otherwise, control flow is
2941 transferred to the default destination.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2942
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2943<h5>Implementation:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2944<p>Depending on properties of the target machine and the particular
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2945 <tt>switch</tt> instruction, this instruction may be code generated in
2946 different ways. For example, it could be generated as a series of chained
2947 conditional branches or with a lookup table.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2948
2949<h5>Example:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2950<pre>
2951 <i>; Emulate a conditional br instruction</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2952 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]2953 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2954
2955 <i>; Emulate an unconditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2956 switch i32 0, label %dest [ ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2957
2958 <i>; Implement a jump table:</i>
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]2959 switch i32 %val, label %otherwise [ i32 0, label %onzero
2960 i32 1, label %onone
2961 i32 2, label %ontwo ]
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2962</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2963
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2964</div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2965
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2966
2967<!-- _______________________________________________________________________ -->
2968<div class="doc_subsubsection">
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2969 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2970</div>
2971
2972<div class="doc_text">
2973
2974<h5>Syntax:</h5>
2975<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2976 indirectbr &lt;somety&gt;* &lt;address&gt;, [ label &lt;dest1&gt;, label &lt;dest2&gt;, ... ]
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2977</pre>
2978
2979<h5>Overview:</h5>
2980
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]2981<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2982 within the current function, whose address is specified by
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2983 "<tt>address</tt>". Address must be derived from a <a
2984 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2985
2986<h5>Arguments:</h5>
2987
2988<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
2989 rest of the arguments indicate the full set of possible destinations that the
2990 address may point to. Blocks are allowed to occur multiple times in the
2991 destination list, though this isn't particularly useful.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2992
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]2993<p>This destination list is required so that dataflow analysis has an accurate
2994 understanding of the CFG.</p>
2995
2996<h5>Semantics:</h5>
2997
2998<p>Control transfers to the block specified in the address argument. All
2999 possible destination blocks must be listed in the label list, otherwise this
3000 instruction has undefined behavior. This implies that jumps to labels
3001 defined in other functions have undefined behavior as well.</p>
3002
3003<h5>Implementation:</h5>
3004
3005<p>This is typically implemented with a jump through a register.</p>
3006
3007<h5>Example:</h5>
3008<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3009 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3010</pre>
3011
3012</div>
3013
3014
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3015<!-- _______________________________________________________________________ -->
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3016<div class="doc_subsubsection">
3017 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
3018</div>
3019
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3020<div class="doc_text">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3021
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3022<h5>Syntax:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3023<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]3024 &lt;result&gt; = invoke [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>] &lt;ptr to function ty&gt; &lt;function ptr val&gt;(&lt;function args&gt;) [<a href="#fnattrs">fn attrs</a>]
Chris Lattner6b7a0082006-05-14 18:23:06 +0000[diff] [blame]3025 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3026</pre>
3027
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3028<h5>Overview:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3029<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3030 function, with the possibility of control flow transfer to either the
3031 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3032 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3033 control flow will return to the "normal" label. If the callee (or any
3034 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3035 instruction, control is interrupted and continued at the dynamically nearest
3036 "exception" label.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3037
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3038<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3039<p>This instruction requires several arguments:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3040
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3041<ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3042 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3043 convention</a> the call should use. If none is specified, the call
3044 defaults to using C calling conventions.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]3045
3046 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3047 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3048 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]3049
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3050 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3051 function value being invoked. In most cases, this is a direct function
3052 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3053 off an arbitrary pointer to function value.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3054
3055 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3056 function to be invoked. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3057
3058 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]3059 signature argument types and parameter attributes. All arguments must be
3060 of <a href="#t_firstclass">first class</a> type. If the function
3061 signature indicates the function accepts a variable number of arguments,
3062 the extra arguments can be specified.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3063
3064 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3065 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3066
3067 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3068 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3069
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]3070 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3071 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3072 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3073</ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3074
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3075<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3076<p>This instruction is designed to operate as a standard
3077 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3078 primary difference is that it establishes an association with a label, which
3079 is used by the runtime library to unwind the stack.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3080
3081<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3082 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3083 exception. Additionally, this is important for implementation of
3084 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3085
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3086<p>For the purposes of the SSA form, the definition of the value returned by the
3087 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3088 block to the "normal" label. If the callee unwinds then no return value is
3089 available.</p>
Dan Gohman9069d892009-05-22 21:47:08 +0000[diff] [blame]3090
Chris Lattner97257f82010-01-15 18:08:37 +0000[diff] [blame]3091<p>Note that the code generator does not yet completely support unwind, and
3092that the invoke/unwind semantics are likely to change in future versions.</p>
3093
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3094<h5>Example:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3095<pre>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]3096 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3097 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]3098 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3099 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3100</pre>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3101
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3102</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3103
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3104<!-- _______________________________________________________________________ -->
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3105
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3106<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
3107Instruction</a> </div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3108
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3109<div class="doc_text">
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3110
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3111<h5>Syntax:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3112<pre>
3113 unwind
3114</pre>
3115
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3116<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3117<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3118 at the first callee in the dynamic call stack which used
3119 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3120 This is primarily used to implement exception handling.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3121
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]3122<h5>Semantics:</h5>
Chris Lattnerfe8519c2008-04-19 21:01:16 +0000[diff] [blame]3123<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3124 immediately halt. The dynamic call stack is then searched for the
3125 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3126 Once found, execution continues at the "exceptional" destination block
3127 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3128 instruction in the dynamic call chain, undefined behavior results.</p>
3129
Chris Lattner97257f82010-01-15 18:08:37 +0000[diff] [blame]3130<p>Note that the code generator does not yet completely support unwind, and
3131that the invoke/unwind semantics are likely to change in future versions.</p>
3132
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3133</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3134
3135<!-- _______________________________________________________________________ -->
3136
3137<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
3138Instruction</a> </div>
3139
3140<div class="doc_text">
3141
3142<h5>Syntax:</h5>
3143<pre>
3144 unreachable
3145</pre>
3146
3147<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3148<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3149 instruction is used to inform the optimizer that a particular portion of the
3150 code is not reachable. This can be used to indicate that the code after a
3151 no-return function cannot be reached, and other facts.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3152
3153<h5>Semantics:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3154<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3155
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3156</div>
3157
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3158<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3159<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3160
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3161<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3162
3163<p>Binary operators are used to do most of the computation in a program. They
3164 require two operands of the same type, execute an operation on them, and
3165 produce a single value. The operands might represent multiple data, as is
3166 the case with the <a href="#t_vector">vector</a> data type. The result value
3167 has the same type as its operands.</p>
3168
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3169<p>There are several different binary operators:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3170
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3171</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3172
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3173<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3174<div class="doc_subsubsection">
3175 <a name="i_add">'<tt>add</tt>' Instruction</a>
3176</div>
3177
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3178<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3179
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3180<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3181<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3182 &lt;result&gt; = add &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohman957b1312009-09-02 17:31:42 +0000[diff] [blame]3183 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3184 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3185 &lt;result&gt; = add nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3186</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3187
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3188<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3189<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3190
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3191<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3192<p>The two arguments to the '<tt>add</tt>' instruction must
3193 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3194 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3195
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3196<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3197<p>The value produced is the integer sum of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3198
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3199<p>If the sum has unsigned overflow, the result returned is the mathematical
3200 result modulo 2<sup>n</sup>, where n is the bit width of the result.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3201
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3202<p>Because LLVM integers use a two's complement representation, this instruction
3203 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3204
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3205<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3206 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3207 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3208 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3209 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3210
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3211<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3212<pre>
3213 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3214</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3215
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3216</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3217
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3218<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3219<div class="doc_subsubsection">
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3220 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
3221</div>
3222
3223<div class="doc_text">
3224
3225<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3226<pre>
3227 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3228</pre>
3229
3230<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3231<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3232
3233<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3234<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3235 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3236 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3237
3238<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3239<p>The value produced is the floating point sum of the two operands.</p>
3240
3241<h5>Example:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3242<pre>
3243 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3244</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3245
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3246</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3247
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3248<!-- _______________________________________________________________________ -->
3249<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3250 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
3251</div>
3252
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3253<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3254
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3255<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3256<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3257 &lt;result&gt; = sub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohman957b1312009-09-02 17:31:42 +0000[diff] [blame]3258 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3259 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3260 &lt;result&gt; = sub nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3261</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3262
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3263<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3264<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3265 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3266
3267<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3268 '<tt>neg</tt>' instruction present in most other intermediate
3269 representations.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3270
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3271<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3272<p>The two arguments to the '<tt>sub</tt>' instruction must
3273 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3274 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3275
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3276<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3277<p>The value produced is the integer difference of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3278
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3279<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3280 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3281 result.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3282
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3283<p>Because LLVM integers use a two's complement representation, this instruction
3284 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3285
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3286<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3287 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3288 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3289 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3290 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3291
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3292<h5>Example:</h5>
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]3293<pre>
3294 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3295 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3296</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3297
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3298</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3299
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3300<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3301<div class="doc_subsubsection">
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3302 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3303</div>
3304
3305<div class="doc_text">
3306
3307<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3308<pre>
3309 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3310</pre>
3311
3312<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3313<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3314 operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3315
3316<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3317 '<tt>fneg</tt>' instruction present in most other intermediate
3318 representations.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3319
3320<h5>Arguments:</h5>
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]3321<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3322 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3323 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3324
3325<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3326<p>The value produced is the floating point difference of the two operands.</p>
3327
3328<h5>Example:</h5>
3329<pre>
3330 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3331 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3332</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3333
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3334</div>
3335
3336<!-- _______________________________________________________________________ -->
3337<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3338 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3339</div>
3340
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3341<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3342
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3343<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3344<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3345 &lt;result&gt; = mul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohman957b1312009-09-02 17:31:42 +0000[diff] [blame]3346 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3347 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3348 &lt;result&gt; = mul nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3349</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3350
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3351<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3352<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3353
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3354<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3355<p>The two arguments to the '<tt>mul</tt>' instruction must
3356 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3357 integer values. Both arguments must have identical types.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3358
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3359<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3360<p>The value produced is the integer product of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3361
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3362<p>If the result of the multiplication has unsigned overflow, the result
3363 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3364 width of the result.</p>
3365
3366<p>Because LLVM integers use a two's complement representation, and the result
3367 is the same width as the operands, this instruction returns the correct
3368 result for both signed and unsigned integers. If a full product
3369 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3370 be sign-extended or zero-extended as appropriate to the width of the full
3371 product.</p>
3372
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3373<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3374 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3375 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3376 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3377 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3378
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3379<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3380<pre>
3381 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3382</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3383
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3384</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3385
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3386<!-- _______________________________________________________________________ -->
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3387<div class="doc_subsubsection">
3388 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3389</div>
3390
3391<div class="doc_text">
3392
3393<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3394<pre>
3395 &lt;result&gt; = fmul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3396</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3397
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3398<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3399<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3400
3401<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3402<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3403 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3404 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3405
3406<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3407<p>The value produced is the floating point product of the two operands.</p>
3408
3409<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3410<pre>
3411 &lt;result&gt; = fmul float 4.0, %var <i>; yields {float}:result = 4.0 * %var</i>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3412</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3413
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3414</div>
3415
3416<!-- _______________________________________________________________________ -->
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3417<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3418</a></div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3419
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3420<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3421
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3422<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3423<pre>
3424 &lt;result&gt; = udiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3425</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3426
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3427<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3428<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3429
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3430<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3431<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3432 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3433 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3434
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3435<h5>Semantics:</h5>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3436<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3437
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3438<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3439 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3440
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3441<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3442
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3443<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3444<pre>
3445 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3446</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3447
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3448</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3449
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3450<!-- _______________________________________________________________________ -->
3451<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3452</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3453
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3454<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3455
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3456<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3457<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3458 &lt;result&gt; = sdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohman957b1312009-09-02 17:31:42 +0000[diff] [blame]3459 &lt;result&gt; = sdiv exact &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3460</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3461
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3462<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3463<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3464
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3465<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3466<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3467 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3468 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3469
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3470<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3471<p>The value produced is the signed integer quotient of the two operands rounded
3472 towards zero.</p>
3473
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3474<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3475 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3476
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3477<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3478 undefined behavior; this is a rare case, but can occur, for example, by doing
3479 a 32-bit division of -2147483648 by -1.</p>
3480
Dan Gohman71dfd782009-07-22 00:04:19 +0000[diff] [blame]3481<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman57255802010-04-23 15:23:32 +0000[diff] [blame]3482 <tt>sdiv</tt> is a <a href="#trapvalues">trap value</a> if the result would
Dan Gohmane501ff72010-07-11 00:08:34 +0000[diff] [blame]3483 be rounded.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3484
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3485<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3486<pre>
3487 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3488</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3489
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3490</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3491
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3492<!-- _______________________________________________________________________ -->
3493<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3494Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3495
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3496<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3497
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3498<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3499<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3500 &lt;result&gt; = fdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3501</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3502
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3503<h5>Overview:</h5>
3504<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3505
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3506<h5>Arguments:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3507<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3508 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3509 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3510
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3511<h5>Semantics:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3512<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3513
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3514<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3515<pre>
3516 &lt;result&gt; = fdiv float 4.0, %var <i>; yields {float}:result = 4.0 / %var</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3517</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3518
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3519</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3520
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3521<!-- _______________________________________________________________________ -->
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3522<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3523</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3524
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3525<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3526
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3527<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3528<pre>
3529 &lt;result&gt; = urem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3530</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3531
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3532<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3533<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3534 division of its two arguments.</p>
3535
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3536<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3537<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3538 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3539 values. Both arguments must have identical types.</p>
3540
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3541<h5>Semantics:</h5>
3542<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3543 This instruction always performs an unsigned division to get the
3544 remainder.</p>
3545
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3546<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3547 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3548
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3549<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3550
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3551<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3552<pre>
3553 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3554</pre>
3555
3556</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3557
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3558<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3559<div class="doc_subsubsection">
3560 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3561</div>
3562
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3563<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3564
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3565<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3566<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3567 &lt;result&gt; = srem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3568</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3569
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3570<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3571<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3572 division of its two operands. This instruction can also take
3573 <a href="#t_vector">vector</a> versions of the values in which case the
3574 elements must be integers.</p>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]3575
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3576<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3577<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3578 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3579 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3580
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3581<h5>Semantics:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3582<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3583 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3584 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3585 a value. For more information about the difference,
3586 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3587 Math Forum</a>. For a table of how this is implemented in various languages,
3588 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3589 Wikipedia: modulo operation</a>.</p>
3590
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3591<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3592 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3593
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3594<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3595 Overflow also leads to undefined behavior; this is a rare case, but can
3596 occur, for example, by taking the remainder of a 32-bit division of
3597 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3598 lets srem be implemented using instructions that return both the result of
3599 the division and the remainder.)</p>
3600
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3601<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3602<pre>
3603 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3604</pre>
3605
3606</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3607
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3608<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3609<div class="doc_subsubsection">
3610 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3611
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3612<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3613
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3614<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3615<pre>
3616 &lt;result&gt; = frem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3617</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3618
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3619<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3620<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3621 its two operands.</p>
3622
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3623<h5>Arguments:</h5>
3624<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3625 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3626 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3627
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3628<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3629<p>This instruction returns the <i>remainder</i> of a division. The remainder
3630 has the same sign as the dividend.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3631
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3632<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3633<pre>
3634 &lt;result&gt; = frem float 4.0, %var <i>; yields {float}:result = 4.0 % %var</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3635</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3636
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3637</div>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]3638
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3639<!-- ======================================================================= -->
3640<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3641Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3642
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3643<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3644
3645<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3646 program. They are generally very efficient instructions and can commonly be
3647 strength reduced from other instructions. They require two operands of the
3648 same type, execute an operation on them, and produce a single value. The
3649 resulting value is the same type as its operands.</p>
3650
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3651</div>
3652
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3653<!-- _______________________________________________________________________ -->
3654<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3655Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3656
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3657<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3658
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3659<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3660<pre>
3661 &lt;result&gt; = shl &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3662</pre>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3663
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3664<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3665<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3666 a specified number of bits.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3667
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3668<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3669<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3670 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3671 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3672
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3673<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3674<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3675 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3676 is (statically or dynamically) negative or equal to or larger than the number
3677 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3678 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3679 shift amount in <tt>op2</tt>.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3680
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3681<h5>Example:</h5>
3682<pre>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3683 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3684 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3685 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3686 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3687 &lt;result&gt; = shl &lt;2 x i32&gt; &lt; i32 1, i32 1&gt;, &lt; i32 1, i32 2&gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 2, i32 4&gt;</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3688</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3689
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3690</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3691
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3692<!-- _______________________________________________________________________ -->
3693<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3694Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3695
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3696<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3697
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3698<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3699<pre>
3700 &lt;result&gt; = lshr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3701</pre>
3702
3703<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3704<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3705 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3706
3707<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3708<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3709 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3710 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3711
3712<h5>Semantics:</h5>
3713<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3714 significant bits of the result will be filled with zero bits after the shift.
3715 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3716 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3717 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3718 shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3719
3720<h5>Example:</h5>
3721<pre>
3722 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3723 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3724 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3725 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3726 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3727 &lt;result&gt; = lshr &lt;2 x i32&gt; &lt; i32 -2, i32 4&gt;, &lt; i32 1, i32 2&gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 0x7FFFFFFF, i32 1&gt;</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3728</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3729
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3730</div>
3731
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3732<!-- _______________________________________________________________________ -->
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3733<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3734Instruction</a> </div>
3735<div class="doc_text">
3736
3737<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3738<pre>
3739 &lt;result&gt; = ashr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3740</pre>
3741
3742<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3743<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3744 operand shifted to the right a specified number of bits with sign
3745 extension.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3746
3747<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3748<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3749 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3750 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3751
3752<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3753<p>This instruction always performs an arithmetic shift right operation, The
3754 most significant bits of the result will be filled with the sign bit
3755 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3756 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3757 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3758 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3759
3760<h5>Example:</h5>
3761<pre>
3762 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3763 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3764 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3765 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3766 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3767 &lt;result&gt; = ashr &lt;2 x i32&gt; &lt; i32 -2, i32 4&gt;, &lt; i32 1, i32 3&gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 -1, i32 0&gt;</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3768</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3769
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3770</div>
3771
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3772<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3773<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3774Instruction</a> </div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3775
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3776<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3777
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3778<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3779<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3780 &lt;result&gt; = and &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3781</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3782
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3783<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3784<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3785 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3786
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3787<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3788<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3789 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3790 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3791
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3792<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3793<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3794
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3795<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3796 <tbody>
3797 <tr>
3798 <td>In0</td>
3799 <td>In1</td>
3800 <td>Out</td>
3801 </tr>
3802 <tr>
3803 <td>0</td>
3804 <td>0</td>
3805 <td>0</td>
3806 </tr>
3807 <tr>
3808 <td>0</td>
3809 <td>1</td>
3810 <td>0</td>
3811 </tr>
3812 <tr>
3813 <td>1</td>
3814 <td>0</td>
3815 <td>0</td>
3816 </tr>
3817 <tr>
3818 <td>1</td>
3819 <td>1</td>
3820 <td>1</td>
3821 </tr>
3822 </tbody>
3823</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3824
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3825<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3826<pre>
3827 &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3828 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3829 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3830</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3831</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3832<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3833<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3834
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3835<div class="doc_text">
3836
3837<h5>Syntax:</h5>
3838<pre>
3839 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3840</pre>
3841
3842<h5>Overview:</h5>
3843<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3844 two operands.</p>
3845
3846<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3847<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3848 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3849 values. Both arguments must have identical types.</p>
3850
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3851<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3852<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3853
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3854<table border="1" cellspacing="0" cellpadding="4">
3855 <tbody>
3856 <tr>
3857 <td>In0</td>
3858 <td>In1</td>
3859 <td>Out</td>
3860 </tr>
3861 <tr>
3862 <td>0</td>
3863 <td>0</td>
3864 <td>0</td>
3865 </tr>
3866 <tr>
3867 <td>0</td>
3868 <td>1</td>
3869 <td>1</td>
3870 </tr>
3871 <tr>
3872 <td>1</td>
3873 <td>0</td>
3874 <td>1</td>
3875 </tr>
3876 <tr>
3877 <td>1</td>
3878 <td>1</td>
3879 <td>1</td>
3880 </tr>
3881 </tbody>
3882</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3883
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3884<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3885<pre>
3886 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3887 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3888 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3889</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3890
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3891</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3892
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3893<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3894<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3895Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3896
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3897<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3898
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3899<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3900<pre>
3901 &lt;result&gt; = xor &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3902</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3903
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3904<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3905<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3906 its two operands. The <tt>xor</tt> is used to implement the "one's
3907 complement" operation, which is the "~" operator in C.</p>
3908
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3909<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3910<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3911 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3912 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3913
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3914<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3915<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3916
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3917<table border="1" cellspacing="0" cellpadding="4">
3918 <tbody>
3919 <tr>
3920 <td>In0</td>
3921 <td>In1</td>
3922 <td>Out</td>
3923 </tr>
3924 <tr>
3925 <td>0</td>
3926 <td>0</td>
3927 <td>0</td>
3928 </tr>
3929 <tr>
3930 <td>0</td>
3931 <td>1</td>
3932 <td>1</td>
3933 </tr>
3934 <tr>
3935 <td>1</td>
3936 <td>0</td>
3937 <td>1</td>
3938 </tr>
3939 <tr>
3940 <td>1</td>
3941 <td>1</td>
3942 <td>0</td>
3943 </tr>
3944 </tbody>
3945</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3946
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3947<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3948<pre>
3949 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3950 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3951 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3952 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3953</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3954
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3955</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3956
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3957<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3958<div class="doc_subsection">
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3959 <a name="vectorops">Vector Operations</a>
3960</div>
3961
3962<div class="doc_text">
3963
3964<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3965 target-independent manner. These instructions cover the element-access and
3966 vector-specific operations needed to process vectors effectively. While LLVM
3967 does directly support these vector operations, many sophisticated algorithms
3968 will want to use target-specific intrinsics to take full advantage of a
3969 specific target.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3970
3971</div>
3972
3973<!-- _______________________________________________________________________ -->
3974<div class="doc_subsubsection">
3975 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3976</div>
3977
3978<div class="doc_text">
3979
3980<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3981<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3982 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3983</pre>
3984
3985<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3986<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3987 from a vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3988
3989
3990<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3991<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3992 of <a href="#t_vector">vector</a> type. The second operand is an index
3993 indicating the position from which to extract the element. The index may be
3994 a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3995
3996<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3997<p>The result is a scalar of the same type as the element type of
3998 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3999 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4000 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4001
4002<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4003<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4004 &lt;result&gt; = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4005</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4006
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4007</div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4008
4009<!-- _______________________________________________________________________ -->
4010<div class="doc_subsubsection">
4011 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
4012</div>
4013
4014<div class="doc_text">
4015
4016<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4017<pre>
Dan Gohman43ba0672008-05-12 23:38:42 +0000[diff] [blame]4018 &lt;result&gt; = insertelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, &lt;ty&gt; &lt;elt&gt;, i32 &lt;idx&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4019</pre>
4020
4021<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4022<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4023 vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4024
4025<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4026<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4027 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4028 whose type must equal the element type of the first operand. The third
4029 operand is an index indicating the position at which to insert the value.
4030 The index may be a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4031
4032<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4033<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4034 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4035 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4036 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4037
4038<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4039<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4040 &lt;result&gt; = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4041</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4042
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4043</div>
4044
4045<!-- _______________________________________________________________________ -->
4046<div class="doc_subsubsection">
4047 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
4048</div>
4049
4050<div class="doc_text">
4051
4052<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4053<pre>
Mon P Wang25f01062008-11-10 04:46:22 +0000[diff] [blame]4054 &lt;result&gt; = shufflevector &lt;n x &lt;ty&gt;&gt; &lt;v1&gt;, &lt;n x &lt;ty&gt;&gt; &lt;v2&gt;, &lt;m x i32&gt; &lt;mask&gt; <i>; yields &lt;m x &lt;ty&gt;&gt;</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4055</pre>
4056
4057<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4058<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4059 from two input vectors, returning a vector with the same element type as the
4060 input and length that is the same as the shuffle mask.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4061
4062<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4063<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4064 with types that match each other. The third argument is a shuffle mask whose
4065 element type is always 'i32'. The result of the instruction is a vector
4066 whose length is the same as the shuffle mask and whose element type is the
4067 same as the element type of the first two operands.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4068
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4069<p>The shuffle mask operand is required to be a constant vector with either
4070 constant integer or undef values.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4071
4072<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4073<p>The elements of the two input vectors are numbered from left to right across
4074 both of the vectors. The shuffle mask operand specifies, for each element of
4075 the result vector, which element of the two input vectors the result element
4076 gets. The element selector may be undef (meaning "don't care") and the
4077 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4078
4079<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4080<pre>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4081 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4082 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4083 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4084 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i> - Identity shuffle.
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4085 &lt;result&gt; = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
Mon P Wang25f01062008-11-10 04:46:22 +0000[diff] [blame]4086 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4087 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Mon P Wang25f01062008-11-10 04:46:22 +0000[diff] [blame]4088 &lt;8 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7 &gt; <i>; yields &lt;8 x i32&gt;</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4089</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4090
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4091</div>
Tanya Lattnerb138bbe2006-04-14 19:24:33 +0000[diff] [blame]4092
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4093<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4094<div class="doc_subsection">
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4095 <a name="aggregateops">Aggregate Operations</a>
4096</div>
4097
4098<div class="doc_text">
4099
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4100<p>LLVM supports several instructions for working with
4101 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4102
4103</div>
4104
4105<!-- _______________________________________________________________________ -->
4106<div class="doc_subsubsection">
4107 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
4108</div>
4109
4110<div class="doc_text">
4111
4112<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4113<pre>
4114 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4115</pre>
4116
4117<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4118<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4119 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4120
4121<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4122<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]4123 of <a href="#t_struct">struct</a> or
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4124 <a href="#t_array">array</a> type. The operands are constant indices to
4125 specify which value to extract in a similar manner as indices in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4126 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4127
4128<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4129<p>The result is the value at the position in the aggregate specified by the
4130 index operands.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4131
4132<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4133<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4134 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4135</pre>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4136
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4137</div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4138
4139<!-- _______________________________________________________________________ -->
4140<div class="doc_subsubsection">
4141 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
4142</div>
4143
4144<div class="doc_text">
4145
4146<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4147<pre>
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]4148 &lt;result&gt; = insertvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;ty&gt; &lt;elt&gt;, &lt;idx&gt; <i>; yields &lt;aggregate type&gt;</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4149</pre>
4150
4151<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4152<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4153 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4154
4155<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4156<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]4157 of <a href="#t_struct">struct</a> or
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4158 <a href="#t_array">array</a> type. The second operand is a first-class
4159 value to insert. The following operands are constant indices indicating
4160 the position at which to insert the value in a similar manner as indices in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4161 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
4162 value to insert must have the same type as the value identified by the
4163 indices.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4164
4165<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4166<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4167 that of <tt>val</tt> except that the value at the position specified by the
4168 indices is that of <tt>elt</tt>.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4169
4170<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4171<pre>
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]4172 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4173 %agg2 = insertvalue {i32, float} %agg1, float %val, 1 <i>; yields {i32 1, float %val}</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4174</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4175
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4176</div>
4177
4178
4179<!-- ======================================================================= -->
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4180<div class="doc_subsection">
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]4181 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4182</div>
4183
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4184<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4185
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4186<p>A key design point of an SSA-based representation is how it represents
4187 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]4188 very simple. This section describes how to read, write, and allocate
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4189 memory in LLVM.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4190
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4191</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4192
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4193<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4194<div class="doc_subsubsection">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4195 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
4196</div>
4197
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4198<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4199
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4200<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4201<pre>
Dan Gohman2140a742010-05-28 01:14:11 +0000[diff] [blame]4202 &lt;result&gt; = alloca &lt;type&gt;[, &lt;ty&gt; &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4203</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4204
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4205<h5>Overview:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4206<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4207 currently executing function, to be automatically released when this function
4208 returns to its caller. The object is always allocated in the generic address
4209 space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4210
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4211<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4212<p>The '<tt>alloca</tt>' instruction
4213 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4214 runtime stack, returning a pointer of the appropriate type to the program.
4215 If "NumElements" is specified, it is the number of elements allocated,
4216 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4217 specified, the value result of the allocation is guaranteed to be aligned to
4218 at least that boundary. If not specified, or if zero, the target can choose
4219 to align the allocation on any convenient boundary compatible with the
4220 type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4221
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4222<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4223
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4224<h5>Semantics:</h5>
Bill Wendling9ee6a312009-05-08 20:49:29 +0000[diff] [blame]4225<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4226 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4227 memory is automatically released when the function returns. The
4228 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4229 variables that must have an address available. When the function returns
4230 (either with the <tt><a href="#i_ret">ret</a></tt>
4231 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4232 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4233
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4234<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4235<pre>
Dan Gohman7a5acb52009-01-04 23:49:44 +0000[diff] [blame]4236 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4237 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4238 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4239 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4240</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4241
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4242</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4243
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4244<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4245<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
4246Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4247
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4248<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4249
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4250<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4251<pre>
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4252 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4253 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4254 !&lt;index&gt; = !{ i32 1 }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4255</pre>
4256
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4257<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4258<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4259
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4260<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4261<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4262 from which to load. The pointer must point to
4263 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4264 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]4265 number or order of execution of this <tt>load</tt> with other <a
4266 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4267
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4268<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4269 operation (that is, the alignment of the memory address). A value of 0 or an
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4270 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4271 alignment for the target. It is the responsibility of the code emitter to
4272 ensure that the alignment information is correct. Overestimating the
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4273 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4274 produce less efficient code. An alignment of 1 is always safe.</p>
4275
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4276<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4277 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4278 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4279 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4280 and code generator that this load is not expected to be reused in the cache.
4281 The code generator may select special instructions to save cache bandwidth,
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4282 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4283
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4284<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4285<p>The location of memory pointed to is loaded. If the value being loaded is of
4286 scalar type then the number of bytes read does not exceed the minimum number
4287 of bytes needed to hold all bits of the type. For example, loading an
4288 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4289 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4290 is undefined if the value was not originally written using a store of the
4291 same type.</p>
4292
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4293<h5>Examples:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4294<pre>
4295 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4296 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4297 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4298</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4299
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4300</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4301
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4302<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4303<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4304Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4305
Reid Spencera89fb182006-11-09 21:18:01 +0000[diff] [blame]4306<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4307
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4308<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4309<pre>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]4310 store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;] <i>; yields {void}</i>
4311 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;] <i>; yields {void}</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4312</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4313
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4314<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4315<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4316
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4317<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4318<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4319 and an address at which to store it. The type of the
4320 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4321 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]4322 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4323 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4324 order of execution of this <tt>store</tt> with other <a
4325 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4326
4327<p>The optional constant "align" argument specifies the alignment of the
4328 operation (that is, the alignment of the memory address). A value of 0 or an
4329 omitted "align" argument means that the operation has the preferential
4330 alignment for the target. It is the responsibility of the code emitter to
4331 ensure that the alignment information is correct. Overestimating the
4332 alignment results in an undefined behavior. Underestimating the alignment may
4333 produce less efficient code. An alignment of 1 is always safe.</p>
4334
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4335<p>The optional !nontemporal metadata must reference a single metatadata
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]4336 name &lt;index&gt; corresponding to a metadata node with one i32 entry of
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4337 value 1. The existence of the !nontemporal metatadata on the
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4338 instruction tells the optimizer and code generator that this load is
4339 not expected to be reused in the cache. The code generator may
4340 select special instructions to save cache bandwidth, such as the
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4341 MOVNT instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4342
4343
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4344<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4345<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4346 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4347 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4348 does not exceed the minimum number of bytes needed to hold all bits of the
4349 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4350 writing a value of a type like <tt>i20</tt> with a size that is not an
4351 integral number of bytes, it is unspecified what happens to the extra bits
4352 that do not belong to the type, but they will typically be overwritten.</p>
4353
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4354<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4355<pre>
4356 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8830ffe2007-10-22 05:10:05 +0000[diff] [blame]4357 store i32 3, i32* %ptr <i>; yields {void}</i>
4358 %val = <a href="#i_load">load</a> i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4359</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4360
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]4361</div>
4362
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4363<!-- _______________________________________________________________________ -->
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4364<div class="doc_subsubsection">
4365 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4366</div>
4367
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4368<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4369
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4370<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4371<pre>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4372 &lt;result&gt; = getelementptr &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]4373 &lt;result&gt; = getelementptr inbounds &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4374</pre>
4375
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4376<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4377<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4378 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4379 It performs address calculation only and does not access memory.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4380
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4381<h5>Arguments:</h5>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4382<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnera40b9122009-07-29 06:44:13 +0000[diff] [blame]4383 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4384 elements of the aggregate object are indexed. The interpretation of each
4385 index is dependent on the type being indexed into. The first index always
4386 indexes the pointer value given as the first argument, the second index
4387 indexes a value of the type pointed to (not necessarily the value directly
4388 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4389 indexed into must be a pointer value, subsequent types can be arrays,
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]4390 vectors, and structs. Note that subsequent types being indexed into
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4391 can never be pointers, since that would require loading the pointer before
4392 continuing calculation.</p>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4393
4394<p>The type of each index argument depends on the type it is indexing into.
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]4395 When indexing into a (optionally packed) structure, only <tt>i32</tt>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4396 integer <b>constants</b> are allowed. When indexing into an array, pointer
4397 or vector, integers of any width are allowed, and they are not required to be
Chris Lattnera40b9122009-07-29 06:44:13 +0000[diff] [blame]4398 constant.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4399
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4400<p>For example, let's consider a C code fragment and how it gets compiled to
4401 LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4402
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]4403<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4404struct RT {
4405 char A;
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4406 int B[10][20];
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4407 char C;
4408};
4409struct ST {
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4410 int X;
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4411 double Y;
4412 struct RT Z;
4413};
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4414
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4415int *foo(struct ST *s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4416 return &amp;s[1].Z.B[5][13];
4417}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4418</pre>
4419
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4420<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4421
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]4422<pre class="doc_code">
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]4423%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4424%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4425
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]4426define i32* @foo(%ST* %s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4427entry:
4428 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4429 ret i32* %reg
4430}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4431</pre>
4432
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4433<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4434<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4435 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4436 }</tt>' type, a structure. The second index indexes into the third element
4437 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4438 i8 }</tt>' type, another structure. The third index indexes into the second
4439 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4440 array. The two dimensions of the array are subscripted into, yielding an
4441 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4442 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4443
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4444<p>Note that it is perfectly legal to index partially through a structure,
4445 returning a pointer to an inner element. Because of this, the LLVM code for
4446 the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4447
4448<pre>
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]4449 define i32* @foo(%ST* %s) {
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4450 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4451 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4452 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4453 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4454 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4455 ret i32* %t5
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4456 }
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4457</pre>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]4458
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]4459<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman57255802010-04-23 15:23:32 +0000[diff] [blame]4460 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
4461 base pointer is not an <i>in bounds</i> address of an allocated object,
4462 or if any of the addresses that would be formed by successive addition of
4463 the offsets implied by the indices to the base address with infinitely
4464 precise arithmetic are not an <i>in bounds</i> address of that allocated
4465 object. The <i>in bounds</i> addresses for an allocated object are all
4466 the addresses that point into the object, plus the address one byte past
4467 the end.</p>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]4468
4469<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4470 the base address with silently-wrapping two's complement arithmetic, and
4471 the result value of the <tt>getelementptr</tt> may be outside the object
4472 pointed to by the base pointer. The result value may not necessarily be
4473 used to access memory though, even if it happens to point into allocated
4474 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4475 section for more information.</p>
4476
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4477<p>The getelementptr instruction is often confusing. For some more insight into
4478 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]4479
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4480<h5>Example:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4481<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4482 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4483 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4484 <i>; yields i8*:vptr</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4485 %vptr = getelementptr {i32, &lt;2 x i8&gt;}* %svptr, i64 0, i32 1, i32 1
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4486 <i>; yields i8*:eptr</i>
4487 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta0c155e62009-04-25 07:27:44 +0000[diff] [blame]4488 <i>; yields i32*:iptr</i>
Sanjiv Gupta77abea02009-04-24 16:38:13 +0000[diff] [blame]4489 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4490</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4491
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4492</div>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]4493
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4494<!-- ======================================================================= -->
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4495<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4496</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4497
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4498<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4499
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4500<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4501 which all take a single operand and a type. They perform various bit
4502 conversions on the operand.</p>
4503
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4504</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4505
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4506<!-- _______________________________________________________________________ -->
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4507<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4508 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4509</div>
4510<div class="doc_text">
4511
4512<h5>Syntax:</h5>
4513<pre>
4514 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4515</pre>
4516
4517<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4518<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4519 type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4520
4521<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4522<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4523 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4524 size and type of the result, which must be
4525 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4526 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4527 allowed.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4528
4529<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4530<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4531 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4532 source size must be larger than the destination size, <tt>trunc</tt> cannot
4533 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4534
4535<h5>Example:</h5>
4536<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4537 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4538 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4539 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4540</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4541
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4542</div>
4543
4544<!-- _______________________________________________________________________ -->
4545<div class="doc_subsubsection">
4546 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4547</div>
4548<div class="doc_text">
4549
4550<h5>Syntax:</h5>
4551<pre>
4552 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4553</pre>
4554
4555<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4556<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4557 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4558
4559
4560<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4561<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4562 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4563 also be of <a href="#t_integer">integer</a> type. The bit size of the
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4564 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4565 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4566
4567<h5>Semantics:</h5>
4568<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4569 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4570
Reid Spencer07c9c682007-01-12 15:46:11 +0000[diff] [blame]4571<p>When zero extending from i1, the result will always be either 0 or 1.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4572
4573<h5>Example:</h5>
4574<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4575 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4576 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4577</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4578
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4579</div>
4580
4581<!-- _______________________________________________________________________ -->
4582<div class="doc_subsubsection">
4583 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4584</div>
4585<div class="doc_text">
4586
4587<h5>Syntax:</h5>
4588<pre>
4589 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4590</pre>
4591
4592<h5>Overview:</h5>
4593<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4594
4595<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4596<p>The '<tt>sext</tt>' instruction takes a value to cast, which must be of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4597 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4598 also be of <a href="#t_integer">integer</a> type. The bit size of the
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4599 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4600 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4601
4602<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4603<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4604 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4605 of the type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4606
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4607<p>When sign extending from i1, the extension always results in -1 or 0.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4608
4609<h5>Example:</h5>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4610<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4611 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4612 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4613</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4614
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4615</div>
4616
4617<!-- _______________________________________________________________________ -->
4618<div class="doc_subsubsection">
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4619 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4620</div>
4621
4622<div class="doc_text">
4623
4624<h5>Syntax:</h5>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4625<pre>
4626 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4627</pre>
4628
4629<h5>Overview:</h5>
4630<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4631 <tt>ty2</tt>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4632
4633<h5>Arguments:</h5>
4634<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4635 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4636 to cast it to. The size of <tt>value</tt> must be larger than the size of
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4637 <tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4638 <i>no-op cast</i>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4639
4640<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4641<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4642 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4643 <a href="#t_floating">floating point</a> type. If the value cannot fit
4644 within the destination type, <tt>ty2</tt>, then the results are
4645 undefined.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4646
4647<h5>Example:</h5>
4648<pre>
4649 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4650 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4651</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4652
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4653</div>
4654
4655<!-- _______________________________________________________________________ -->
4656<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4657 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4658</div>
4659<div class="doc_text">
4660
4661<h5>Syntax:</h5>
4662<pre>
4663 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4664</pre>
4665
4666<h5>Overview:</h5>
4667<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4668 floating point value.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4669
4670<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4671<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4672 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4673 a <a href="#t_floating">floating point</a> type to cast it to. The source
4674 type must be smaller than the destination type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4675
4676<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4677<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4678 <a href="#t_floating">floating point</a> type to a larger
4679 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4680 used to make a <i>no-op cast</i> because it always changes bits. Use
4681 <tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4682
4683<h5>Example:</h5>
4684<pre>
4685 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4686 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4687</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4688
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4689</div>
4690
4691<!-- _______________________________________________________________________ -->
4692<div class="doc_subsubsection">
Reid Spencer2eadb532007-01-21 00:29:26 +0000[diff] [blame]4693 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4694</div>
4695<div class="doc_text">
4696
4697<h5>Syntax:</h5>
4698<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4699 &lt;result&gt; = fptoui &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4700</pre>
4701
4702<h5>Overview:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4703<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4704 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4705
4706<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4707<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4708 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4709 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4710 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4711 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4712
4713<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4714<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4715 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4716 towards zero) unsigned integer value. If the value cannot fit
4717 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4718
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4719<h5>Example:</h5>
4720<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4721 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]4722 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4723 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4724</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4725
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4726</div>
4727
4728<!-- _______________________________________________________________________ -->
4729<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4730 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4731</div>
4732<div class="doc_text">
4733
4734<h5>Syntax:</h5>
4735<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4736 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4737</pre>
4738
4739<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4740<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4741 <a href="#t_floating">floating point</a> <tt>value</tt> to
4742 type <tt>ty2</tt>.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4743
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4744<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4745<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4746 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4747 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4748 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4749 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4750
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4751<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4752<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4753 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4754 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4755 the results are undefined.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4756
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]4757<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4758<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4759 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]4760 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4761 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4762</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4763
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4764</div>
4765
4766<!-- _______________________________________________________________________ -->
4767<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4768 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4769</div>
4770<div class="doc_text">
4771
4772<h5>Syntax:</h5>
4773<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4774 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4775</pre>
4776
4777<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4778<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4779 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4780
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4781<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]4782<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4783 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4784 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4785 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4786 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4787
4788<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4789<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4790 integer quantity and converts it to the corresponding floating point
4791 value. If the value cannot fit in the floating point value, the results are
4792 undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4793
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4794<h5>Example:</h5>
4795<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4796 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4797 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4798</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4799
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4800</div>
4801
4802<!-- _______________________________________________________________________ -->
4803<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4804 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4805</div>
4806<div class="doc_text">
4807
4808<h5>Syntax:</h5>
4809<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4810 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4811</pre>
4812
4813<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4814<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4815 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4816
4817<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]4818<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4819 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4820 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4821 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4822 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4823
4824<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4825<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4826 quantity and converts it to the corresponding floating point value. If the
4827 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4828
4829<h5>Example:</h5>
4830<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4831 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4832 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4833</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4834
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4835</div>
4836
4837<!-- _______________________________________________________________________ -->
4838<div class="doc_subsubsection">
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4839 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4840</div>
4841<div class="doc_text">
4842
4843<h5>Syntax:</h5>
4844<pre>
4845 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4846</pre>
4847
4848<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4849<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4850 the integer type <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4851
4852<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4853<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4854 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4855 <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4856
4857<h5>Semantics:</h5>
4858<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4859 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4860 truncating or zero extending that value to the size of the integer type. If
4861 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4862 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4863 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4864 change.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4865
4866<h5>Example:</h5>
4867<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4868 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4869 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4870</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4871
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4872</div>
4873
4874<!-- _______________________________________________________________________ -->
4875<div class="doc_subsubsection">
4876 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4877</div>
4878<div class="doc_text">
4879
4880<h5>Syntax:</h5>
4881<pre>
4882 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4883</pre>
4884
4885<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4886<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4887 pointer type, <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4888
4889<h5>Arguments:</h5>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]4890<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4891 value to cast, and a type to cast it to, which must be a
4892 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4893
4894<h5>Semantics:</h5>
4895<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4896 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4897 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4898 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4899 than the size of a pointer then a zero extension is done. If they are the
4900 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4901
4902<h5>Example:</h5>
4903<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4904 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]4905 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4906 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4907</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4908
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4909</div>
4910
4911<!-- _______________________________________________________________________ -->
4912<div class="doc_subsubsection">
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4913 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4914</div>
4915<div class="doc_text">
4916
4917<h5>Syntax:</h5>
4918<pre>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4919 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4920</pre>
4921
4922<h5>Overview:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4923<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4924 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4925
4926<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4927<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4928 non-aggregate first class value, and a type to cast it to, which must also be
4929 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4930 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4931 identical. If the source type is a pointer, the destination type must also be
4932 a pointer. This instruction supports bitwise conversion of vectors to
4933 integers and to vectors of other types (as long as they have the same
4934 size).</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4935
4936<h5>Semantics:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4937<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4938 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4939 this conversion. The conversion is done as if the <tt>value</tt> had been
4940 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4941 be converted to other pointer types with this instruction. To convert
4942 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4943 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4944
4945<h5>Example:</h5>
4946<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4947 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4948 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4949 %Z = bitcast &lt;2 x int&gt; %V to i64; <i>; yields i64: %V</i>
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]4950</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4951
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4952</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4953
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4954<!-- ======================================================================= -->
4955<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4956
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4957<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4958
4959<p>The instructions in this category are the "miscellaneous" instructions, which
4960 defy better classification.</p>
4961
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4962</div>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4963
4964<!-- _______________________________________________________________________ -->
4965<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4966</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4967
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4968<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4969
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4970<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4971<pre>
4972 &lt;result&gt; = icmp &lt;cond&gt; &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {i1} or {&lt;N x i1&gt;}:result</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4973</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4974
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4975<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4976<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4977 boolean values based on comparison of its two integer, integer vector, or
4978 pointer operands.</p>
4979
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4980<h5>Arguments:</h5>
4981<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4982 the condition code indicating the kind of comparison to perform. It is not a
4983 value, just a keyword. The possible condition code are:</p>
4984
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4985<ol>
4986 <li><tt>eq</tt>: equal</li>
4987 <li><tt>ne</tt>: not equal </li>
4988 <li><tt>ugt</tt>: unsigned greater than</li>
4989 <li><tt>uge</tt>: unsigned greater or equal</li>
4990 <li><tt>ult</tt>: unsigned less than</li>
4991 <li><tt>ule</tt>: unsigned less or equal</li>
4992 <li><tt>sgt</tt>: signed greater than</li>
4993 <li><tt>sge</tt>: signed greater or equal</li>
4994 <li><tt>slt</tt>: signed less than</li>
4995 <li><tt>sle</tt>: signed less or equal</li>
4996</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4997
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]4998<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4999 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5000 typed. They must also be identical types.</p>
5001
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5002<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5003<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5004 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]5005 either an <a href="#t_integer"><tt>i1</tt></a> or vector of <tt>i1</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5006 result, as follows:</p>
5007
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5008<ol>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5009 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5010 <tt>false</tt> otherwise. No sign interpretation is necessary or
5011 performed.</li>
5012
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5013 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5014 <tt>false</tt> otherwise. No sign interpretation is necessary or
5015 performed.</li>
5016
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5017 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5018 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5019
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5020 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5021 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5022 to <tt>op2</tt>.</li>
5023
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5024 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5025 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5026
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5027 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5028 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5029
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5030 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5031 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5032
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5033 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5034 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5035 to <tt>op2</tt>.</li>
5036
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5037 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5038 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5039
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5040 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5041 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5042</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5043
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5044<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5045 values are compared as if they were integers.</p>
5046
5047<p>If the operands are integer vectors, then they are compared element by
5048 element. The result is an <tt>i1</tt> vector with the same number of elements
5049 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5050
5051<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5052<pre>
5053 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5054 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5055 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5056 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5057 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5058 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5059</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5060
5061<p>Note that the code generator does not yet support vector types with
5062 the <tt>icmp</tt> instruction.</p>
5063
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5064</div>
5065
5066<!-- _______________________________________________________________________ -->
5067<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5068</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5069
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5070<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5071
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5072<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5073<pre>
5074 &lt;result&gt; = fcmp &lt;cond&gt; &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {i1} or {&lt;N x i1&gt;}:result</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5075</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5076
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5077<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5078<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5079 values based on comparison of its operands.</p>
5080
5081<p>If the operands are floating point scalars, then the result type is a boolean
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]5082(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5083
5084<p>If the operands are floating point vectors, then the result type is a vector
5085 of boolean with the same number of elements as the operands being
5086 compared.</p>
5087
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5088<h5>Arguments:</h5>
5089<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5090 the condition code indicating the kind of comparison to perform. It is not a
5091 value, just a keyword. The possible condition code are:</p>
5092
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5093<ol>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5094 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5095 <li><tt>oeq</tt>: ordered and equal</li>
5096 <li><tt>ogt</tt>: ordered and greater than </li>
5097 <li><tt>oge</tt>: ordered and greater than or equal</li>
5098 <li><tt>olt</tt>: ordered and less than </li>
5099 <li><tt>ole</tt>: ordered and less than or equal</li>
5100 <li><tt>one</tt>: ordered and not equal</li>
5101 <li><tt>ord</tt>: ordered (no nans)</li>
5102 <li><tt>ueq</tt>: unordered or equal</li>
5103 <li><tt>ugt</tt>: unordered or greater than </li>
5104 <li><tt>uge</tt>: unordered or greater than or equal</li>
5105 <li><tt>ult</tt>: unordered or less than </li>
5106 <li><tt>ule</tt>: unordered or less than or equal</li>
5107 <li><tt>une</tt>: unordered or not equal</li>
5108 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5109 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5110</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5111
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5112<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5113 <i>unordered</i> means that either operand may be a QNAN.</p>
5114
5115<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5116 a <a href="#t_floating">floating point</a> type or
5117 a <a href="#t_vector">vector</a> of floating point type. They must have
5118 identical types.</p>
5119
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5120<h5>Semantics:</h5>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]5121<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5122 according to the condition code given as <tt>cond</tt>. If the operands are
5123 vectors, then the vectors are compared element by element. Each comparison
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]5124 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5125 follows:</p>
5126
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5127<ol>
5128 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5129
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5130 <li><tt>oeq</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5131 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5132
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5133 <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5134 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5135
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5136 <li><tt>oge</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5137 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5138
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5139 <li><tt>olt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5140 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5141
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5142 <li><tt>ole</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5143 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5144
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5145 <li><tt>one</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5146 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5147
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5148 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5149
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5150 <li><tt>ueq</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5151 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5152
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5153 <li><tt>ugt</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5154 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5155
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5156 <li><tt>uge</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5157 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5158
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5159 <li><tt>ult</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5160 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5161
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5162 <li><tt>ule</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5163 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5164
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5165 <li><tt>une</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5166 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5167
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5168 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5169
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5170 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5171</ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5172
5173<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5174<pre>
5175 &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
Dan Gohmanc579d972008-09-09 01:02:47 +0000[diff] [blame]5176 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5177 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5178 &lt;result&gt; = fcmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5179</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5180
5181<p>Note that the code generator does not yet support vector types with
5182 the <tt>fcmp</tt> instruction.</p>
5183
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5184</div>
5185
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5186<!-- _______________________________________________________________________ -->
Nate Begemand2195702008-05-12 19:01:56 +0000[diff] [blame]5187<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5188 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
5189</div>
5190
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5191<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5192
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5193<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5194<pre>
5195 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5196</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5197
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5198<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5199<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5200 SSA graph representing the function.</p>
5201
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5202<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5203<p>The type of the incoming values is specified with the first type field. After
5204 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5205 one pair for each predecessor basic block of the current block. Only values
5206 of <a href="#t_firstclass">first class</a> type may be used as the value
5207 arguments to the PHI node. Only labels may be used as the label
5208 arguments.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5209
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5210<p>There must be no non-phi instructions between the start of a basic block and
5211 the PHI instructions: i.e. PHI instructions must be first in a basic
5212 block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5213
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5214<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5215 occur on the edge from the corresponding predecessor block to the current
5216 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5217 value on the same edge).</p>
Jay Foad1a4eea52009-06-03 10:20:10 +0000[diff] [blame]5218
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5219<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5220<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5221 specified by the pair corresponding to the predecessor basic block that
5222 executed just prior to the current block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5223
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5224<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]5225<pre>
5226Loop: ; Infinite loop that counts from 0 on up...
5227 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5228 %nextindvar = add i32 %indvar, 1
5229 br label %Loop
5230</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5231
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5232</div>
5233
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5234<!-- _______________________________________________________________________ -->
5235<div class="doc_subsubsection">
5236 <a name="i_select">'<tt>select</tt>' Instruction</a>
5237</div>
5238
5239<div class="doc_text">
5240
5241<h5>Syntax:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5242<pre>
Dan Gohmanc579d972008-09-09 01:02:47 +0000[diff] [blame]5243 &lt;result&gt; = select <i>selty</i> &lt;cond&gt;, &lt;ty&gt; &lt;val1&gt;, &lt;ty&gt; &lt;val2&gt; <i>; yields ty</i>
5244
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5245 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5246</pre>
5247
5248<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5249<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5250 condition, without branching.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5251
5252
5253<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5254<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5255 values indicating the condition, and two values of the
5256 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5257 vectors and the condition is a scalar, then entire vectors are selected, not
5258 individual elements.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5259
5260<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5261<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5262 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5263
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5264<p>If the condition is a vector of i1, then the value arguments must be vectors
5265 of the same size, and the selection is done element by element.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5266
5267<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5268<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5269 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5270</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5271
5272<p>Note that the code generator does not yet support conditions
5273 with vector type.</p>
5274
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5275</div>
5276
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]5277<!-- _______________________________________________________________________ -->
5278<div class="doc_subsubsection">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5279 <a name="i_call">'<tt>call</tt>' Instruction</a>
5280</div>
5281
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5282<div class="doc_text">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5283
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5284<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5285<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]5286 &lt;result&gt; = [tail] call [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>] &lt;ty&gt; [&lt;fnty&gt;*] &lt;fnptrval&gt;(&lt;function args&gt;) [<a href="#fnattrs">fn attrs</a>]
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5287</pre>
5288
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5289<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5290<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5291
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5292<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5293<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5294
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5295<ol>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5296 <li>The optional "tail" marker indicates that the callee function does not
5297 access any allocas or varargs in the caller. Note that calls may be
5298 marked "tail" even if they do not occur before
5299 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5300 present, the function call is eligible for tail call optimization,
5301 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Cheng59676492010-03-08 21:05:02 +0000[diff] [blame]5302 optimized into a jump</a>. The code generator may optimize calls marked
5303 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5304 sibling call optimization</a> when the caller and callee have
5305 matching signatures, or 2) forced tail call optimization when the
5306 following extra requirements are met:
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5307 <ul>
5308 <li>Caller and callee both have the calling
5309 convention <tt>fastcc</tt>.</li>
5310 <li>The call is in tail position (ret immediately follows call and ret
5311 uses value of call or is void).</li>
5312 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohman6232f732010-03-02 01:08:11 +0000[diff] [blame]5313 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5314 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5315 constraints are met.</a></li>
5316 </ul>
5317 </li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5318
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5319 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5320 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]5321 defaults to using C calling conventions. The calling convention of the
5322 call must match the calling convention of the target function, or else the
5323 behavior is undefined.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5324
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5325 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5326 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5327 '<tt>inreg</tt>' attributes are valid here.</li>
5328
5329 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5330 type of the return value. Functions that return no value are marked
5331 <tt><a href="#t_void">void</a></tt>.</li>
5332
5333 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5334 being invoked. The argument types must match the types implied by this
5335 signature. This type can be omitted if the function is not varargs and if
5336 the function type does not return a pointer to a function.</li>
5337
5338 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5339 be invoked. In most cases, this is a direct function invocation, but
5340 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5341 to function value.</li>
5342
5343 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]5344 signature argument types and parameter attributes. All arguments must be
5345 of <a href="#t_firstclass">first class</a> type. If the function
5346 signature indicates the function accepts a variable number of arguments,
5347 the extra arguments can be specified.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5348
5349 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5350 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5351 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5352</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5353
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5354<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5355<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5356 a specified function, with its incoming arguments bound to the specified
5357 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5358 function, control flow continues with the instruction after the function
5359 call, and the return value of the function is bound to the result
5360 argument.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5361
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5362<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5363<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]5364 %retval = call i32 @test(i32 %argc)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]5365 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattnerfb7c88d2008-03-21 17:24:17 +0000[diff] [blame]5366 %X = tail call i32 @foo() <i>; yields i32</i>
5367 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5368 call void %foo(i8 97 signext)
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]5369
5370 %struct.A = type { i32, i8 }
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5371 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]5372 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5373 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner6cbe8e92008-10-08 06:26:11 +0000[diff] [blame]5374 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmaneefa7df2008-10-07 10:03:45 +0000[diff] [blame]5375 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5376</pre>
5377
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]5378<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen722212d2009-09-25 17:04:42 +0000[diff] [blame]5379standard C99 library as being the C99 library functions, and may perform
5380optimizations or generate code for them under that assumption. This is
5381something we'd like to change in the future to provide better support for
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5382freestanding environments and non-C-based languages.</p>
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]5383
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5384</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5385
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5386<!-- _______________________________________________________________________ -->
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5387<div class="doc_subsubsection">
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]5388 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5389</div>
5390
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5391<div class="doc_text">
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5392
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5393<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5394<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5395 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5396</pre>
5397
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5398<h5>Overview:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5399<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5400 the "variable argument" area of a function call. It is used to implement the
5401 <tt>va_arg</tt> macro in C.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5402
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5403<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5404<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5405 argument. It returns a value of the specified argument type and increments
5406 the <tt>va_list</tt> to point to the next argument. The actual type
5407 of <tt>va_list</tt> is target specific.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5408
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5409<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5410<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5411 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5412 to the next argument. For more information, see the variable argument
5413 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5414
5415<p>It is legal for this instruction to be called in a function which does not
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5416 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5417 function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5418
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5419<p><tt>va_arg</tt> is an LLVM instruction instead of
5420 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5421 argument.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5422
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5423<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5424<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5425
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5426<p>Note that the code generator does not yet fully support va_arg on many
5427 targets. Also, it does not currently support va_arg with aggregate types on
5428 any target.</p>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]5429
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5430</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5431
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5432<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]5433<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5434<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5435
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5436<div class="doc_text">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5437
5438<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5439 well known names and semantics and are required to follow certain
5440 restrictions. Overall, these intrinsics represent an extension mechanism for
5441 the LLVM language that does not require changing all of the transformations
5442 in LLVM when adding to the language (or the bitcode reader/writer, the
5443 parser, etc...).</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5444
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]5445<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5446 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5447 begin with this prefix. Intrinsic functions must always be external
5448 functions: you cannot define the body of intrinsic functions. Intrinsic
5449 functions may only be used in call or invoke instructions: it is illegal to
5450 take the address of an intrinsic function. Additionally, because intrinsic
5451 functions are part of the LLVM language, it is required if any are added that
5452 they be documented here.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5453
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5454<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5455 family of functions that perform the same operation but on different data
5456 types. Because LLVM can represent over 8 million different integer types,
5457 overloading is used commonly to allow an intrinsic function to operate on any
5458 integer type. One or more of the argument types or the result type can be
5459 overloaded to accept any integer type. Argument types may also be defined as
5460 exactly matching a previous argument's type or the result type. This allows
5461 an intrinsic function which accepts multiple arguments, but needs all of them
5462 to be of the same type, to only be overloaded with respect to a single
5463 argument or the result.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5464
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5465<p>Overloaded intrinsics will have the names of its overloaded argument types
5466 encoded into its function name, each preceded by a period. Only those types
5467 which are overloaded result in a name suffix. Arguments whose type is matched
5468 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5469 can take an integer of any width and returns an integer of exactly the same
5470 integer width. This leads to a family of functions such as
5471 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5472 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5473 suffix is required. Because the argument's type is matched against the return
5474 type, it does not require its own name suffix.</p>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]5475
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5476<p>To learn how to add an intrinsic function, please see the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5477 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5478
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5479</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5480
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5481<!-- ======================================================================= -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5482<div class="doc_subsection">
5483 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5484</div>
5485
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5486<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5487
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5488<p>Variable argument support is defined in LLVM with
5489 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5490 intrinsic functions. These functions are related to the similarly named
5491 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5492
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5493<p>All of these functions operate on arguments that use a target-specific value
5494 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5495 not define what this type is, so all transformations should be prepared to
5496 handle these functions regardless of the type used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5497
Chris Lattner30b868d2006-05-15 17:26:46 +0000[diff] [blame]5498<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5499 instruction and the variable argument handling intrinsic functions are
5500 used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5501
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]5502<pre class="doc_code">
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5503define i32 @test(i32 %X, ...) {
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5504 ; Initialize variable argument processing
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5505 %ap = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5506 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5507 call void @llvm.va_start(i8* %ap2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5508
5509 ; Read a single integer argument
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5510 %tmp = va_arg i8** %ap, i32
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5511
5512 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5513 %aq = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5514 %aq2 = bitcast i8** %aq to i8*
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5515 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5516 call void @llvm.va_end(i8* %aq2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5517
5518 ; Stop processing of arguments.
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5519 call void @llvm.va_end(i8* %ap2)
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5520 ret i32 %tmp
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5521}
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5522
5523declare void @llvm.va_start(i8*)
5524declare void @llvm.va_copy(i8*, i8*)
5525declare void @llvm.va_end(i8*)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5526</pre>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5527
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5528</div>
5529
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5530<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5531<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5532 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5533</div>
5534
5535
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5536<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5537
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5538<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5539<pre>
5540 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5541</pre>
5542
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5543<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5544<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5545 for subsequent use by <tt><a href="#i_va_arg">va_arg</a></tt>.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5546
5547<h5>Arguments:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5548<p>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5549
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5550<h5>Semantics:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5551<p>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5552 macro available in C. In a target-dependent way, it initializes
5553 the <tt>va_list</tt> element to which the argument points, so that the next
5554 call to <tt>va_arg</tt> will produce the first variable argument passed to
5555 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5556 need to know the last argument of the function as the compiler can figure
5557 that out.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5558
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5559</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5560
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5561<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5562<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5563 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5564</div>
5565
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5566<div class="doc_text">
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5567
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5568<h5>Syntax:</h5>
5569<pre>
5570 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5571</pre>
5572
5573<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5574<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5575 which has been initialized previously
5576 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5577 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5578
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5579<h5>Arguments:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5580<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5581
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5582<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5583<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5584 macro available in C. In a target-dependent way, it destroys
5585 the <tt>va_list</tt> element to which the argument points. Calls
5586 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5587 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5588 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5589
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5590</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5591
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5592<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5593<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5594 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5595</div>
5596
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5597<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5598
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5599<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5600<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5601 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5602</pre>
5603
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5604<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5605<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5606 from the source argument list to the destination argument list.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5607
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5608<h5>Arguments:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5609<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5610 The second argument is a pointer to a <tt>va_list</tt> element to copy
5611 from.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5612
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5613<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5614<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5615 macro available in C. In a target-dependent way, it copies the
5616 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5617 element. This intrinsic is necessary because
5618 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5619 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5620
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5621</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5622
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5623<!-- ======================================================================= -->
5624<div class="doc_subsection">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5625 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5626</div>
5627
5628<div class="doc_text">
5629
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5630<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]5631Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5632intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5633roots on the stack</a>, as well as garbage collector implementations that
5634require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5635barriers. Front-ends for type-safe garbage collected languages should generate
5636these intrinsics to make use of the LLVM garbage collectors. For more details,
5637see <a href="GarbageCollection.html">Accurate Garbage Collection with
5638LLVM</a>.</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]5639
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5640<p>The garbage collection intrinsics only operate on objects in the generic
5641 address space (address space zero).</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]5642
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5643</div>
5644
5645<!-- _______________________________________________________________________ -->
5646<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5647 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5648</div>
5649
5650<div class="doc_text">
5651
5652<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5653<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5654 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5655</pre>
5656
5657<h5>Overview:</h5>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]5658<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5659 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5660
5661<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5662<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5663 root pointer. The second pointer (which must be either a constant or a
5664 global value address) contains the meta-data to be associated with the
5665 root.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5666
5667<h5>Semantics:</h5>
Chris Lattner851b7712008-04-24 05:59:56 +0000[diff] [blame]5668<p>At runtime, a call to this intrinsic stores a null pointer into the "ptrloc"
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5669 location. At compile-time, the code generator generates information to allow
5670 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5671 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5672 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5673
5674</div>
5675
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5676<!-- _______________________________________________________________________ -->
5677<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5678 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5679</div>
5680
5681<div class="doc_text">
5682
5683<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5684<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5685 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5686</pre>
5687
5688<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5689<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5690 locations, allowing garbage collector implementations that require read
5691 barriers.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5692
5693<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]5694<p>The second argument is the address to read from, which should be an address
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5695 allocated from the garbage collector. The first object is a pointer to the
5696 start of the referenced object, if needed by the language runtime (otherwise
5697 null).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5698
5699<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5700<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5701 instruction, but may be replaced with substantially more complex code by the
5702 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5703 may only be used in a function which <a href="#gc">specifies a GC
5704 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5705
5706</div>
5707
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5708<!-- _______________________________________________________________________ -->
5709<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5710 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5711</div>
5712
5713<div class="doc_text">
5714
5715<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5716<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5717 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5718</pre>
5719
5720<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5721<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5722 locations, allowing garbage collector implementations that require write
5723 barriers (such as generational or reference counting collectors).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5724
5725<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]5726<p>The first argument is the reference to store, the second is the start of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5727 object to store it to, and the third is the address of the field of Obj to
5728 store to. If the runtime does not require a pointer to the object, Obj may
5729 be null.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5730
5731<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5732<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5733 instruction, but may be replaced with substantially more complex code by the
5734 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5735 may only be used in a function which <a href="#gc">specifies a GC
5736 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5737
5738</div>
5739
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5740<!-- ======================================================================= -->
5741<div class="doc_subsection">
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5742 <a name="int_codegen">Code Generator Intrinsics</a>
5743</div>
5744
5745<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5746
5747<p>These intrinsics are provided by LLVM to expose special features that may
5748 only be implemented with code generator support.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5749
5750</div>
5751
5752<!-- _______________________________________________________________________ -->
5753<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5754 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5755</div>
5756
5757<div class="doc_text">
5758
5759<h5>Syntax:</h5>
5760<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5761 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5762</pre>
5763
5764<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5765<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5766 target-specific value indicating the return address of the current function
5767 or one of its callers.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5768
5769<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5770<p>The argument to this intrinsic indicates which function to return the address
5771 for. Zero indicates the calling function, one indicates its caller, etc.
5772 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5773
5774<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5775<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5776 indicating the return address of the specified call frame, or zero if it
5777 cannot be identified. The value returned by this intrinsic is likely to be
5778 incorrect or 0 for arguments other than zero, so it should only be used for
5779 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5780
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5781<p>Note that calling this intrinsic does not prevent function inlining or other
5782 aggressive transformations, so the value returned may not be that of the
5783 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5784
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5785</div>
5786
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5787<!-- _______________________________________________________________________ -->
5788<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5789 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5790</div>
5791
5792<div class="doc_text">
5793
5794<h5>Syntax:</h5>
5795<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]5796 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5797</pre>
5798
5799<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5800<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5801 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5802
5803<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5804<p>The argument to this intrinsic indicates which function to return the frame
5805 pointer for. Zero indicates the calling function, one indicates its caller,
5806 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5807
5808<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5809<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5810 indicating the frame address of the specified call frame, or zero if it
5811 cannot be identified. The value returned by this intrinsic is likely to be
5812 incorrect or 0 for arguments other than zero, so it should only be used for
5813 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5814
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5815<p>Note that calling this intrinsic does not prevent function inlining or other
5816 aggressive transformations, so the value returned may not be that of the
5817 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5818
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5819</div>
5820
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5821<!-- _______________________________________________________________________ -->
5822<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5823 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5824</div>
5825
5826<div class="doc_text">
5827
5828<h5>Syntax:</h5>
5829<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]5830 declare i8* @llvm.stacksave()
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5831</pre>
5832
5833<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5834<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5835 of the function stack, for use
5836 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5837 useful for implementing language features like scoped automatic variable
5838 sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5839
5840<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5841<p>This intrinsic returns a opaque pointer value that can be passed
5842 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5843 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5844 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5845 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5846 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5847 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5848
5849</div>
5850
5851<!-- _______________________________________________________________________ -->
5852<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5853 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5854</div>
5855
5856<div class="doc_text">
5857
5858<h5>Syntax:</h5>
5859<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]5860 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5861</pre>
5862
5863<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5864<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5865 the function stack to the state it was in when the
5866 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5867 executed. This is useful for implementing language features like scoped
5868 automatic variable sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5869
5870<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5871<p>See the description
5872 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5873
5874</div>
5875
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5876<!-- _______________________________________________________________________ -->
5877<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5878 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5879</div>
5880
5881<div class="doc_text">
5882
5883<h5>Syntax:</h5>
5884<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5885 declare void @llvm.prefetch(i8* &lt;address&gt;, i32 &lt;rw&gt;, i32 &lt;locality&gt;)
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5886</pre>
5887
5888<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5889<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5890 insert a prefetch instruction if supported; otherwise, it is a noop.
5891 Prefetches have no effect on the behavior of the program but can change its
5892 performance characteristics.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5893
5894<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5895<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5896 specifier determining if the fetch should be for a read (0) or write (1),
5897 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5898 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5899 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5900
5901<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5902<p>This intrinsic does not modify the behavior of the program. In particular,
5903 prefetches cannot trap and do not produce a value. On targets that support
5904 this intrinsic, the prefetch can provide hints to the processor cache for
5905 better performance.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5906
5907</div>
5908
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5909<!-- _______________________________________________________________________ -->
5910<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5911 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5912</div>
5913
5914<div class="doc_text">
5915
5916<h5>Syntax:</h5>
5917<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5918 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5919</pre>
5920
5921<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5922<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5923 Counter (PC) in a region of code to simulators and other tools. The method
5924 is target specific, but it is expected that the marker will use exported
5925 symbols to transmit the PC of the marker. The marker makes no guarantees
5926 that it will remain with any specific instruction after optimizations. It is
5927 possible that the presence of a marker will inhibit optimizations. The
5928 intended use is to be inserted after optimizations to allow correlations of
5929 simulation runs.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5930
5931<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5932<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5933
5934<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5935<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5936 not support this intrinsic may ignore it.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5937
5938</div>
5939
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5940<!-- _______________________________________________________________________ -->
5941<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5942 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5943</div>
5944
5945<div class="doc_text">
5946
5947<h5>Syntax:</h5>
5948<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]5949 declare i64 @llvm.readcyclecounter()
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5950</pre>
5951
5952<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5953<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5954 counter register (or similar low latency, high accuracy clocks) on those
5955 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5956 should map to RPCC. As the backing counters overflow quickly (on the order
5957 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5958
5959<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5960<p>When directly supported, reading the cycle counter should not modify any
5961 memory. Implementations are allowed to either return a application specific
5962 value or a system wide value. On backends without support, this is lowered
5963 to a constant 0.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5964
5965</div>
5966
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5967<!-- ======================================================================= -->
5968<div class="doc_subsection">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5969 <a name="int_libc">Standard C Library Intrinsics</a>
5970</div>
5971
5972<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5973
5974<p>LLVM provides intrinsics for a few important standard C library functions.
5975 These intrinsics allow source-language front-ends to pass information about
5976 the alignment of the pointer arguments to the code generator, providing
5977 opportunity for more efficient code generation.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5978
5979</div>
5980
5981<!-- _______________________________________________________________________ -->
5982<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5983 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5984</div>
5985
5986<div class="doc_text">
5987
5988<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5989<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
Mon P Wang508127b2010-04-07 06:35:53 +0000[diff] [blame]5990 integer bit width and for different address spaces. Not all targets support
5991 all bit widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5992
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5993<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]5994 declare void @llvm.memcpy.p0i8.p0i8.i32(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]5995 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]5996 declare void @llvm.memcpy.p0i8.p0i8.i64(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]5997 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5998</pre>
5999
6000<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6001<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6002 source location to the destination location.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6003
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6004<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6005 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6006 and the pointers can be in specified address spaces.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6007
6008<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6009
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6010<p>The first argument is a pointer to the destination, the second is a pointer
6011 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6012 number of bytes to copy, the fourth argument is the alignment of the
6013 source and destination locations, and the fifth is a boolean indicating a
6014 volatile access.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6015
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6016<p>If the call to this intrinsic has an alignment value that is not 0 or 1,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6017 then the caller guarantees that both the source and destination pointers are
6018 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]6019
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6020<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6021 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6022 The detailed access behavior is not very cleanly specified and it is unwise
6023 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6024
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6025<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6026
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6027<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6028 source location to the destination location, which are not allowed to
6029 overlap. It copies "len" bytes of memory over. If the argument is known to
6030 be aligned to some boundary, this can be specified as the fourth argument,
6031 otherwise it should be set to 0 or 1.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6032
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6033</div>
6034
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6035<!-- _______________________________________________________________________ -->
6036<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6037 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6038</div>
6039
6040<div class="doc_text">
6041
6042<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]6043<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
Mon P Wang508127b2010-04-07 06:35:53 +0000[diff] [blame]6044 width and for different address space. Not all targets support all bit
6045 widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6046
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6047<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6048 declare void @llvm.memmove.p0i8.p0i8.i32(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6049 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6050 declare void @llvm.memmove.p0i8.p0i8.i64(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6051 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6052</pre>
6053
6054<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6055<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6056 source location to the destination location. It is similar to the
6057 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6058 overlap.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6059
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6060<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6061 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6062 and the pointers can be in specified address spaces.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6063
6064<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6065
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6066<p>The first argument is a pointer to the destination, the second is a pointer
6067 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6068 number of bytes to copy, the fourth argument is the alignment of the
6069 source and destination locations, and the fifth is a boolean indicating a
6070 volatile access.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6071
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6072<p>If the call to this intrinsic has an alignment value that is not 0 or 1,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6073 then the caller guarantees that the source and destination pointers are
6074 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]6075
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6076<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6077 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6078 The detailed access behavior is not very cleanly specified and it is unwise
6079 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6080
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6081<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6082
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6083<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6084 source location to the destination location, which may overlap. It copies
6085 "len" bytes of memory over. If the argument is known to be aligned to some
6086 boundary, this can be specified as the fourth argument, otherwise it should
6087 be set to 0 or 1.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6088
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6089</div>
6090
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6091<!-- _______________________________________________________________________ -->
6092<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6093 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6094</div>
6095
6096<div class="doc_text">
6097
6098<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]6099<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]6100 width and for different address spaces. However, not all targets support all
6101 bit widths.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6102
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6103<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6104 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]6105 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6106 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]6107 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6108</pre>
6109
6110<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6111<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6112 particular byte value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6113
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6114<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]6115 intrinsic does not return a value and takes extra alignment/volatile
6116 arguments. Also, the destination can be in an arbitrary address space.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6117
6118<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6119<p>The first argument is a pointer to the destination to fill, the second is the
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]6120 byte value with which to fill it, the third argument is an integer argument
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6121 specifying the number of bytes to fill, and the fourth argument is the known
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]6122 alignment of the destination location.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6123
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6124<p>If the call to this intrinsic has an alignment value that is not 0 or 1,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6125 then the caller guarantees that the destination pointer is aligned to that
6126 boundary.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6127
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6128<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6129 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6130 The detailed access behavior is not very cleanly specified and it is unwise
6131 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6132
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6133<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6134<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6135 at the destination location. If the argument is known to be aligned to some
6136 boundary, this can be specified as the fourth argument, otherwise it should
6137 be set to 0 or 1.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6138
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6139</div>
6140
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]6141<!-- _______________________________________________________________________ -->
6142<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6143 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6144</div>
6145
6146<div class="doc_text">
6147
6148<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6149<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6150 floating point or vector of floating point type. Not all targets support all
6151 types however.</p>
6152
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6153<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]6154 declare float @llvm.sqrt.f32(float %Val)
6155 declare double @llvm.sqrt.f64(double %Val)
6156 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6157 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6158 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6159</pre>
6160
6161<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6162<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6163 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6164 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6165 behavior for negative numbers other than -0.0 (which allows for better
6166 optimization, because there is no need to worry about errno being
6167 set). <tt>llvm.sqrt(-0.0)</tt> is defined to return -0.0 like IEEE sqrt.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6168
6169<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6170<p>The argument and return value are floating point numbers of the same
6171 type.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6172
6173<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6174<p>This function returns the sqrt of the specified operand if it is a
6175 nonnegative floating point number.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6176
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]6177</div>
6178
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6179<!-- _______________________________________________________________________ -->
6180<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6181 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6182</div>
6183
6184<div class="doc_text">
6185
6186<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6187<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6188 floating point or vector of floating point type. Not all targets support all
6189 types however.</p>
6190
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6191<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]6192 declare float @llvm.powi.f32(float %Val, i32 %power)
6193 declare double @llvm.powi.f64(double %Val, i32 %power)
6194 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6195 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6196 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6197</pre>
6198
6199<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6200<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6201 specified (positive or negative) power. The order of evaluation of
6202 multiplications is not defined. When a vector of floating point type is
6203 used, the second argument remains a scalar integer value.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6204
6205<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6206<p>The second argument is an integer power, and the first is a value to raise to
6207 that power.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6208
6209<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6210<p>This function returns the first value raised to the second power with an
6211 unspecified sequence of rounding operations.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6212
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]6213</div>
6214
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6215<!-- _______________________________________________________________________ -->
6216<div class="doc_subsubsection">
6217 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
6218</div>
6219
6220<div class="doc_text">
6221
6222<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6223<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6224 floating point or vector of floating point type. Not all targets support all
6225 types however.</p>
6226
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6227<pre>
6228 declare float @llvm.sin.f32(float %Val)
6229 declare double @llvm.sin.f64(double %Val)
6230 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6231 declare fp128 @llvm.sin.f128(fp128 %Val)
6232 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6233</pre>
6234
6235<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6236<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6237
6238<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6239<p>The argument and return value are floating point numbers of the same
6240 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6241
6242<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6243<p>This function returns the sine of the specified operand, returning the same
6244 values as the libm <tt>sin</tt> functions would, and handles error conditions
6245 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6246
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6247</div>
6248
6249<!-- _______________________________________________________________________ -->
6250<div class="doc_subsubsection">
6251 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
6252</div>
6253
6254<div class="doc_text">
6255
6256<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6257<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6258 floating point or vector of floating point type. Not all targets support all
6259 types however.</p>
6260
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6261<pre>
6262 declare float @llvm.cos.f32(float %Val)
6263 declare double @llvm.cos.f64(double %Val)
6264 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6265 declare fp128 @llvm.cos.f128(fp128 %Val)
6266 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6267</pre>
6268
6269<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6270<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6271
6272<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6273<p>The argument and return value are floating point numbers of the same
6274 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6275
6276<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6277<p>This function returns the cosine of the specified operand, returning the same
6278 values as the libm <tt>cos</tt> functions would, and handles error conditions
6279 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6280
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6281</div>
6282
6283<!-- _______________________________________________________________________ -->
6284<div class="doc_subsubsection">
6285 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
6286</div>
6287
6288<div class="doc_text">
6289
6290<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6291<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6292 floating point or vector of floating point type. Not all targets support all
6293 types however.</p>
6294
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6295<pre>
6296 declare float @llvm.pow.f32(float %Val, float %Power)
6297 declare double @llvm.pow.f64(double %Val, double %Power)
6298 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6299 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6300 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6301</pre>
6302
6303<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6304<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6305 specified (positive or negative) power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6306
6307<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6308<p>The second argument is a floating point power, and the first is a value to
6309 raise to that power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6310
6311<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6312<p>This function returns the first value raised to the second power, returning
6313 the same values as the libm <tt>pow</tt> functions would, and handles error
6314 conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6315
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]6316</div>
6317
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6318<!-- ======================================================================= -->
6319<div class="doc_subsection">
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6320 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6321</div>
6322
6323<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6324
6325<p>LLVM provides intrinsics for a few important bit manipulation operations.
6326 These allow efficient code generation for some algorithms.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6327
6328</div>
6329
6330<!-- _______________________________________________________________________ -->
6331<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6332 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6333</div>
6334
6335<div class="doc_text">
6336
6337<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6338<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6339 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6340
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6341<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6342 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6343 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6344 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6345</pre>
6346
6347<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6348<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6349 values with an even number of bytes (positive multiple of 16 bits). These
6350 are useful for performing operations on data that is not in the target's
6351 native byte order.</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6352
6353<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6354<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6355 and low byte of the input i16 swapped. Similarly,
6356 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6357 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6358 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6359 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6360 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6361 more, respectively).</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6362
6363</div>
6364
6365<!-- _______________________________________________________________________ -->
6366<div class="doc_subsubsection">
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]6367 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6368</div>
6369
6370<div class="doc_text">
6371
6372<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6373<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6374 width. Not all targets support all bit widths however.</p>
6375
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6376<pre>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6377 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6378 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6379 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6380 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6381 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6382</pre>
6383
6384<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6385<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6386 in a value.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6387
6388<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6389<p>The only argument is the value to be counted. The argument may be of any
6390 integer type. The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6391
6392<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6393<p>The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6394
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6395</div>
6396
6397<!-- _______________________________________________________________________ -->
6398<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]6399 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6400</div>
6401
6402<div class="doc_text">
6403
6404<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6405<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6406 integer bit width. Not all targets support all bit widths however.</p>
6407
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6408<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6409 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6410 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6411 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6412 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6413 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6414</pre>
6415
6416<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6417<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6418 leading zeros in a variable.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6419
6420<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6421<p>The only argument is the value to be counted. The argument may be of any
6422 integer type. The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6423
6424<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6425<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6426 zeros in a variable. If the src == 0 then the result is the size in bits of
6427 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6428
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6429</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]6430
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6431<!-- _______________________________________________________________________ -->
6432<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]6433 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6434</div>
6435
6436<div class="doc_text">
6437
6438<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6439<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6440 integer bit width. Not all targets support all bit widths however.</p>
6441
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6442<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6443 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6444 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6445 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6446 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6447 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6448</pre>
6449
6450<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6451<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6452 trailing zeros.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6453
6454<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6455<p>The only argument is the value to be counted. The argument may be of any
6456 integer type. The return type must match the argument type.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6457
6458<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6459<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6460 zeros in a variable. If the src == 0 then the result is the size in bits of
6461 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6462
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6463</div>
6464
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6465<!-- ======================================================================= -->
6466<div class="doc_subsection">
6467 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6468</div>
6469
6470<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6471
6472<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6473
6474</div>
6475
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6476<!-- _______________________________________________________________________ -->
6477<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6478 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6479</div>
6480
6481<div class="doc_text">
6482
6483<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6484<p>This is an overloaded intrinsic. You can use <tt>llvm.sadd.with.overflow</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6485 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6486
6487<pre>
6488 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6489 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6490 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6491</pre>
6492
6493<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6494<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6495 a signed addition of the two arguments, and indicate whether an overflow
6496 occurred during the signed summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6497
6498<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6499<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6500 be of integer types of any bit width, but they must have the same bit
6501 width. The second element of the result structure must be of
6502 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6503 undergo signed addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6504
6505<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6506<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6507 a signed addition of the two variables. They return a structure &mdash; the
6508 first element of which is the signed summation, and the second element of
6509 which is a bit specifying if the signed summation resulted in an
6510 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6511
6512<h5>Examples:</h5>
6513<pre>
6514 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6515 %sum = extractvalue {i32, i1} %res, 0
6516 %obit = extractvalue {i32, i1} %res, 1
6517 br i1 %obit, label %overflow, label %normal
6518</pre>
6519
6520</div>
6521
6522<!-- _______________________________________________________________________ -->
6523<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6524 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6525</div>
6526
6527<div class="doc_text">
6528
6529<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6530<p>This is an overloaded intrinsic. You can use <tt>llvm.uadd.with.overflow</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6531 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6532
6533<pre>
6534 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6535 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6536 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6537</pre>
6538
6539<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6540<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6541 an unsigned addition of the two arguments, and indicate whether a carry
6542 occurred during the unsigned summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6543
6544<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6545<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6546 be of integer types of any bit width, but they must have the same bit
6547 width. The second element of the result structure must be of
6548 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6549 undergo unsigned addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6550
6551<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6552<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6553 an unsigned addition of the two arguments. They return a structure &mdash;
6554 the first element of which is the sum, and the second element of which is a
6555 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6556
6557<h5>Examples:</h5>
6558<pre>
6559 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6560 %sum = extractvalue {i32, i1} %res, 0
6561 %obit = extractvalue {i32, i1} %res, 1
6562 br i1 %obit, label %carry, label %normal
6563</pre>
6564
6565</div>
6566
6567<!-- _______________________________________________________________________ -->
6568<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6569 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6570</div>
6571
6572<div class="doc_text">
6573
6574<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6575<p>This is an overloaded intrinsic. You can use <tt>llvm.ssub.with.overflow</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6576 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6577
6578<pre>
6579 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6580 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6581 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6582</pre>
6583
6584<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6585<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6586 a signed subtraction of the two arguments, and indicate whether an overflow
6587 occurred during the signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6588
6589<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6590<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6591 be of integer types of any bit width, but they must have the same bit
6592 width. The second element of the result structure must be of
6593 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6594 undergo signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6595
6596<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6597<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6598 a signed subtraction of the two arguments. They return a structure &mdash;
6599 the first element of which is the subtraction, and the second element of
6600 which is a bit specifying if the signed subtraction resulted in an
6601 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6602
6603<h5>Examples:</h5>
6604<pre>
6605 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6606 %sum = extractvalue {i32, i1} %res, 0
6607 %obit = extractvalue {i32, i1} %res, 1
6608 br i1 %obit, label %overflow, label %normal
6609</pre>
6610
6611</div>
6612
6613<!-- _______________________________________________________________________ -->
6614<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6615 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6616</div>
6617
6618<div class="doc_text">
6619
6620<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6621<p>This is an overloaded intrinsic. You can use <tt>llvm.usub.with.overflow</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6622 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6623
6624<pre>
6625 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6626 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6627 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6628</pre>
6629
6630<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6631<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6632 an unsigned subtraction of the two arguments, and indicate whether an
6633 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6634
6635<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6636<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6637 be of integer types of any bit width, but they must have the same bit
6638 width. The second element of the result structure must be of
6639 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6640 undergo unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6641
6642<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6643<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6644 an unsigned subtraction of the two arguments. They return a structure &mdash;
6645 the first element of which is the subtraction, and the second element of
6646 which is a bit specifying if the unsigned subtraction resulted in an
6647 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6648
6649<h5>Examples:</h5>
6650<pre>
6651 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6652 %sum = extractvalue {i32, i1} %res, 0
6653 %obit = extractvalue {i32, i1} %res, 1
6654 br i1 %obit, label %overflow, label %normal
6655</pre>
6656
6657</div>
6658
6659<!-- _______________________________________________________________________ -->
6660<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6661 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6662</div>
6663
6664<div class="doc_text">
6665
6666<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6667<p>This is an overloaded intrinsic. You can use <tt>llvm.smul.with.overflow</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6668 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6669
6670<pre>
6671 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6672 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6673 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6674</pre>
6675
6676<h5>Overview:</h5>
6677
6678<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6679 a signed multiplication of the two arguments, and indicate whether an
6680 overflow occurred during the signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6681
6682<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6683<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6684 be of integer types of any bit width, but they must have the same bit
6685 width. The second element of the result structure must be of
6686 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6687 undergo signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6688
6689<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6690<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6691 a signed multiplication of the two arguments. They return a structure &mdash;
6692 the first element of which is the multiplication, and the second element of
6693 which is a bit specifying if the signed multiplication resulted in an
6694 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6695
6696<h5>Examples:</h5>
6697<pre>
6698 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6699 %sum = extractvalue {i32, i1} %res, 0
6700 %obit = extractvalue {i32, i1} %res, 1
6701 br i1 %obit, label %overflow, label %normal
6702</pre>
6703
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]6704</div>
6705
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6706<!-- _______________________________________________________________________ -->
6707<div class="doc_subsubsection">
6708 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6709</div>
6710
6711<div class="doc_text">
6712
6713<h5>Syntax:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6714<p>This is an overloaded intrinsic. You can use <tt>llvm.umul.with.overflow</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6715 on any integer bit width.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6716
6717<pre>
6718 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6719 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6720 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6721</pre>
6722
6723<h5>Overview:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6724<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6725 a unsigned multiplication of the two arguments, and indicate whether an
6726 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6727
6728<h5>Arguments:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6729<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6730 be of integer types of any bit width, but they must have the same bit
6731 width. The second element of the result structure must be of
6732 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6733 undergo unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6734
6735<h5>Semantics:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6736<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6737 an unsigned multiplication of the two arguments. They return a structure
6738 &mdash; the first element of which is the multiplication, and the second
6739 element of which is a bit specifying if the unsigned multiplication resulted
6740 in an overflow.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6741
6742<h5>Examples:</h5>
6743<pre>
6744 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6745 %sum = extractvalue {i32, i1} %res, 0
6746 %obit = extractvalue {i32, i1} %res, 1
6747 br i1 %obit, label %overflow, label %normal
6748</pre>
6749
6750</div>
6751
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6752<!-- ======================================================================= -->
6753<div class="doc_subsection">
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6754 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
6755</div>
6756
6757<div class="doc_text">
6758
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6759<p>Half precision floating point is a storage-only format. This means that it is
6760 a dense encoding (in memory) but does not support computation in the
6761 format.</p>
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6762
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6763<p>This means that code must first load the half-precision floating point
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6764 value as an i16, then convert it to float with <a
6765 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
6766 Computation can then be performed on the float value (including extending to
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6767 double etc). To store the value back to memory, it is first converted to
6768 float if needed, then converted to i16 with
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6769 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
6770 storing as an i16 value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6771</div>
6772
6773<!-- _______________________________________________________________________ -->
6774<div class="doc_subsubsection">
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6775 <a name="int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6776</div>
6777
6778<div class="doc_text">
6779
6780<h5>Syntax:</h5>
6781<pre>
6782 declare i16 @llvm.convert.to.fp16(f32 %a)
6783</pre>
6784
6785<h5>Overview:</h5>
6786<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6787 a conversion from single precision floating point format to half precision
6788 floating point format.</p>
6789
6790<h5>Arguments:</h5>
6791<p>The intrinsic function contains single argument - the value to be
6792 converted.</p>
6793
6794<h5>Semantics:</h5>
6795<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6796 a conversion from single precision floating point format to half precision
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6797 floating point format. The return value is an <tt>i16</tt> which
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6798 contains the converted number.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6799
6800<h5>Examples:</h5>
6801<pre>
6802 %res = call i16 @llvm.convert.to.fp16(f32 %a)
6803 store i16 %res, i16* @x, align 2
6804</pre>
6805
6806</div>
6807
6808<!-- _______________________________________________________________________ -->
6809<div class="doc_subsubsection">
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6810 <a name="int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6811</div>
6812
6813<div class="doc_text">
6814
6815<h5>Syntax:</h5>
6816<pre>
6817 declare f32 @llvm.convert.from.fp16(i16 %a)
6818</pre>
6819
6820<h5>Overview:</h5>
6821<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
6822 a conversion from half precision floating point format to single precision
6823 floating point format.</p>
6824
6825<h5>Arguments:</h5>
6826<p>The intrinsic function contains single argument - the value to be
6827 converted.</p>
6828
6829<h5>Semantics:</h5>
6830<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]6831 conversion from half single precision floating point format to single
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]6832 precision floating point format. The input half-float value is represented by
6833 an <tt>i16</tt> value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]6834
6835<h5>Examples:</h5>
6836<pre>
6837 %a = load i16* @x, align 2
6838 %res = call f32 @llvm.convert.from.fp16(i16 %a)
6839</pre>
6840
6841</div>
6842
6843<!-- ======================================================================= -->
6844<div class="doc_subsection">
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6845 <a name="int_debugger">Debugger Intrinsics</a>
6846</div>
6847
6848<div class="doc_text">
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6849
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6850<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6851 prefix), are described in
6852 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6853 Level Debugging</a> document.</p>
6854
6855</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6856
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]6857<!-- ======================================================================= -->
6858<div class="doc_subsection">
6859 <a name="int_eh">Exception Handling Intrinsics</a>
6860</div>
6861
6862<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6863
6864<p>The LLVM exception handling intrinsics (which all start with
6865 <tt>llvm.eh.</tt> prefix), are described in
6866 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6867 Handling</a> document.</p>
6868
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]6869</div>
6870
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]6871<!-- ======================================================================= -->
6872<div class="doc_subsection">
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]6873 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6874</div>
6875
6876<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6877
6878<p>This intrinsic makes it possible to excise one parameter, marked with
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]6879 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
6880 The result is a callable
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6881 function pointer lacking the nest parameter - the caller does not need to
6882 provide a value for it. Instead, the value to use is stored in advance in a
6883 "trampoline", a block of memory usually allocated on the stack, which also
6884 contains code to splice the nest value into the argument list. This is used
6885 to implement the GCC nested function address extension.</p>
6886
6887<p>For example, if the function is
6888 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6889 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6890 follows:</p>
6891
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]6892<pre class="doc_code">
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]6893 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6894 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]6895 %p = call i8* @llvm.init.trampoline(i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval)
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]6896 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6897</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6898
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]6899<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
6900 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6901
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6902</div>
6903
6904<!-- _______________________________________________________________________ -->
6905<div class="doc_subsubsection">
6906 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6907</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6908
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6909<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6910
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6911<h5>Syntax:</h5>
6912<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6913 declare i8* @llvm.init.trampoline(i8* &lt;tramp&gt;, i8* &lt;func&gt;, i8* &lt;nval&gt;)
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6914</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6915
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6916<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6917<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6918 function pointer suitable for executing it.</p>
6919
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6920<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6921<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6922 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6923 sufficiently aligned block of memory; this memory is written to by the
6924 intrinsic. Note that the size and the alignment are target-specific - LLVM
6925 currently provides no portable way of determining them, so a front-end that
6926 generates this intrinsic needs to have some target-specific knowledge.
6927 The <tt>func</tt> argument must hold a function bitcast to
6928 an <tt>i8*</tt>.</p>
6929
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6930<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6931<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6932 dependent code, turning it into a function. A pointer to this function is
6933 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6934 function pointer type</a> before being called. The new function's signature
6935 is the same as that of <tt>func</tt> with any arguments marked with
6936 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6937 is allowed, and it must be of pointer type. Calling the new function is
6938 equivalent to calling <tt>func</tt> with the same argument list, but
6939 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6940 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6941 by <tt>tramp</tt> is modified, then the effect of any later call to the
6942 returned function pointer is undefined.</p>
6943
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6944</div>
6945
6946<!-- ======================================================================= -->
6947<div class="doc_subsection">
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6948 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6949</div>
6950
6951<div class="doc_text">
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6952
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6953<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6954 hardware constructs for atomic operations and memory synchronization. This
6955 provides an interface to the hardware, not an interface to the programmer. It
6956 is aimed at a low enough level to allow any programming models or APIs
6957 (Application Programming Interfaces) which need atomic behaviors to map
6958 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6959 hardware provides a "universal IR" for source languages, it also provides a
6960 starting point for developing a "universal" atomic operation and
6961 synchronization IR.</p>
6962
6963<p>These do <em>not</em> form an API such as high-level threading libraries,
6964 software transaction memory systems, atomic primitives, and intrinsic
6965 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6966 application libraries. The hardware interface provided by LLVM should allow
6967 a clean implementation of all of these APIs and parallel programming models.
6968 No one model or paradigm should be selected above others unless the hardware
6969 itself ubiquitously does so.</p>
6970
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6971</div>
6972
6973<!-- _______________________________________________________________________ -->
6974<div class="doc_subsubsection">
6975 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6976</div>
6977<div class="doc_text">
6978<h5>Syntax:</h5>
6979<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]6980 declare void @llvm.memory.barrier(i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt;, i1 &lt;device&gt;)
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6981</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6982
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6983<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6984<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6985 specific pairs of memory access types.</p>
6986
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6987<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6988<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6989 The first four arguments enables a specific barrier as listed below. The
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6990 fifth argument specifies that the barrier applies to io or device or uncached
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6991 memory.</p>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6992
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6993<ul>
6994 <li><tt>ll</tt>: load-load barrier</li>
6995 <li><tt>ls</tt>: load-store barrier</li>
6996 <li><tt>sl</tt>: store-load barrier</li>
6997 <li><tt>ss</tt>: store-store barrier</li>
6998 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
6999</ul>
7000
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7001<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7002<p>This intrinsic causes the system to enforce some ordering constraints upon
7003 the loads and stores of the program. This barrier does not
7004 indicate <em>when</em> any events will occur, it only enforces
7005 an <em>order</em> in which they occur. For any of the specified pairs of load
7006 and store operations (f.ex. load-load, or store-load), all of the first
7007 operations preceding the barrier will complete before any of the second
7008 operations succeeding the barrier begin. Specifically the semantics for each
7009 pairing is as follows:</p>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7010
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7011<ul>
7012 <li><tt>ll</tt>: All loads before the barrier must complete before any load
7013 after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7014 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7015 store after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7016 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7017 store after the barrier begins.</li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7018 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7019 load after the barrier begins.</li>
7020</ul>
7021
7022<p>These semantics are applied with a logical "and" behavior when more than one
7023 is enabled in a single memory barrier intrinsic.</p>
7024
7025<p>Backends may implement stronger barriers than those requested when they do
7026 not support as fine grained a barrier as requested. Some architectures do
7027 not need all types of barriers and on such architectures, these become
7028 noops.</p>
7029
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7030<h5>Example:</h5>
7031<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7032%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7033%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7034 store i32 4, %ptr
7035
7036%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7037 call void @llvm.memory.barrier(i1 false, i1 true, i1 false, i1 false)
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7038 <i>; guarantee the above finishes</i>
7039 store i32 8, %ptr <i>; before this begins</i>
7040</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7041
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7042</div>
7043
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7044<!-- _______________________________________________________________________ -->
7045<div class="doc_subsubsection">
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7046 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7047</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7048
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7049<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7050
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7051<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7052<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
7053 any integer bit width and for different address spaces. Not all targets
7054 support all bit widths however.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7055
7056<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7057 declare i8 @llvm.atomic.cmp.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt;)
7058 declare i16 @llvm.atomic.cmp.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt;)
7059 declare i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt;)
7060 declare i64 @llvm.atomic.cmp.swap.i64.p0i64(i64* &lt;ptr&gt;, i64 &lt;cmp&gt;, i64 &lt;val&gt;)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7061</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7062
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7063<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7064<p>This loads a value in memory and compares it to a given value. If they are
7065 equal, it stores a new value into the memory.</p>
7066
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7067<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7068<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
7069 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
7070 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
7071 this integer type. While any bit width integer may be used, targets may only
7072 lower representations they support in hardware.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7073
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7074<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7075<p>This entire intrinsic must be executed atomically. It first loads the value
7076 in memory pointed to by <tt>ptr</tt> and compares it with the
7077 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
7078 memory. The loaded value is yielded in all cases. This provides the
7079 equivalent of an atomic compare-and-swap operation within the SSA
7080 framework.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7081
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7082<h5>Examples:</h5>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7083<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7084%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7085%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7086 store i32 4, %ptr
7087
7088%val1 = add i32 4, 4
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7089%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 4, %val1)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7090 <i>; yields {i32}:result1 = 4</i>
7091%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7092%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7093
7094%val2 = add i32 1, 1
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7095%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 5, %val2)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7096 <i>; yields {i32}:result2 = 8</i>
7097%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
7098
7099%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
7100</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7101
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7102</div>
7103
7104<!-- _______________________________________________________________________ -->
7105<div class="doc_subsubsection">
7106 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
7107</div>
7108<div class="doc_text">
7109<h5>Syntax:</h5>
7110
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7111<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
7112 integer bit width. Not all targets support all bit widths however.</p>
7113
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7114<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7115 declare i8 @llvm.atomic.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;val&gt;)
7116 declare i16 @llvm.atomic.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;val&gt;)
7117 declare i32 @llvm.atomic.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;val&gt;)
7118 declare i64 @llvm.atomic.swap.i64.p0i64(i64* &lt;ptr&gt;, i64 &lt;val&gt;)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7119</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7120
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7121<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7122<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
7123 the value from memory. It then stores the value in <tt>val</tt> in the memory
7124 at <tt>ptr</tt>.</p>
7125
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7126<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7127<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
7128 the <tt>val</tt> argument and the result must be integers of the same bit
7129 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
7130 integer type. The targets may only lower integer representations they
7131 support.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7132
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7133<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7134<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
7135 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
7136 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7137
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7138<h5>Examples:</h5>
7139<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7140%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7141%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7142 store i32 4, %ptr
7143
7144%val1 = add i32 4, 4
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7145%result1 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val1)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7146 <i>; yields {i32}:result1 = 4</i>
7147%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7148%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7149
7150%val2 = add i32 1, 1
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7151%result2 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val2)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7152 <i>; yields {i32}:result2 = 8</i>
7153
7154%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
7155%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
7156</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7157
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7158</div>
7159
7160<!-- _______________________________________________________________________ -->
7161<div class="doc_subsubsection">
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7162 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7163
7164</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7165
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7166<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7167
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7168<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7169<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
7170 any integer bit width. Not all targets support all bit widths however.</p>
7171
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7172<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7173 declare i8 @llvm.atomic.load.add.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7174 declare i16 @llvm.atomic.load.add.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7175 declare i32 @llvm.atomic.load.add.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7176 declare i64 @llvm.atomic.load.add.i64.p0i64(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7177</pre>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7178
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7179<h5>Overview:</h5>
7180<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
7181 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7182
7183<h5>Arguments:</h5>
7184<p>The intrinsic takes two arguments, the first a pointer to an integer value
7185 and the second an integer value. The result is also an integer value. These
7186 integer types can have any bit width, but they must all have the same bit
7187 width. The targets may only lower integer representations they support.</p>
7188
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7189<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7190<p>This intrinsic does a series of operations atomically. It first loads the
7191 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
7192 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7193
7194<h5>Examples:</h5>
7195<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7196%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7197%ptr = bitcast i8* %mallocP to i32*
7198 store i32 4, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7199%result1 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 4)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7200 <i>; yields {i32}:result1 = 4</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7201%result2 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 2)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7202 <i>; yields {i32}:result2 = 8</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7203%result3 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 5)
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7204 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7205%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7206</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7207
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]7208</div>
7209
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7210<!-- _______________________________________________________________________ -->
7211<div class="doc_subsubsection">
7212 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
7213
7214</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7215
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7216<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7217
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7218<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7219<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
7220 any integer bit width and for different address spaces. Not all targets
7221 support all bit widths however.</p>
7222
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7223<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7224 declare i8 @llvm.atomic.load.sub.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7225 declare i16 @llvm.atomic.load.sub.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7226 declare i32 @llvm.atomic.load.sub.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7227 declare i64 @llvm.atomic.load.sub.i64.p0i32(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7228</pre>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7229
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7230<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7231<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7232 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7233
7234<h5>Arguments:</h5>
7235<p>The intrinsic takes two arguments, the first a pointer to an integer value
7236 and the second an integer value. The result is also an integer value. These
7237 integer types can have any bit width, but they must all have the same bit
7238 width. The targets may only lower integer representations they support.</p>
7239
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7240<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7241<p>This intrinsic does a series of operations atomically. It first loads the
7242 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
7243 result to <tt>ptr</tt>. It yields the original value stored
7244 at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7245
7246<h5>Examples:</h5>
7247<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7248%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7249%ptr = bitcast i8* %mallocP to i32*
7250 store i32 8, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7251%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 4)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7252 <i>; yields {i32}:result1 = 8</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7253%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 2)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7254 <i>; yields {i32}:result2 = 4</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7255%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 5)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7256 <i>; yields {i32}:result3 = 2</i>
7257%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
7258</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7259
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7260</div>
7261
7262<!-- _______________________________________________________________________ -->
7263<div class="doc_subsubsection">
7264 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
7265 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
7266 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
7267 <a name="int_atomic_load_xor">'<tt>llvm.atomic.load.xor.*</tt>' Intrinsic</a><br>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7268</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7269
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7270<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7271
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7272<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7273<p>These are overloaded intrinsics. You can
7274 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
7275 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
7276 bit width and for different address spaces. Not all targets support all bit
7277 widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7278
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7279<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7280 declare i8 @llvm.atomic.load.and.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7281 declare i16 @llvm.atomic.load.and.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7282 declare i32 @llvm.atomic.load.and.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7283 declare i64 @llvm.atomic.load.and.i64.p0i64(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7284</pre>
7285
7286<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7287 declare i8 @llvm.atomic.load.or.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7288 declare i16 @llvm.atomic.load.or.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7289 declare i32 @llvm.atomic.load.or.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7290 declare i64 @llvm.atomic.load.or.i64.p0i64(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7291</pre>
7292
7293<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7294 declare i8 @llvm.atomic.load.nand.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7295 declare i16 @llvm.atomic.load.nand.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7296 declare i32 @llvm.atomic.load.nand.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7297 declare i64 @llvm.atomic.load.nand.i64.p0i32(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7298</pre>
7299
7300<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7301 declare i8 @llvm.atomic.load.xor.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7302 declare i16 @llvm.atomic.load.xor.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7303 declare i32 @llvm.atomic.load.xor.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7304 declare i64 @llvm.atomic.load.xor.i64.p0i32(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7305</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7306
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7307<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7308<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
7309 the value stored in memory at <tt>ptr</tt>. It yields the original value
7310 at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7311
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7312<h5>Arguments:</h5>
7313<p>These intrinsics take two arguments, the first a pointer to an integer value
7314 and the second an integer value. The result is also an integer value. These
7315 integer types can have any bit width, but they must all have the same bit
7316 width. The targets may only lower integer representations they support.</p>
7317
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7318<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7319<p>These intrinsics does a series of operations atomically. They first load the
7320 value stored at <tt>ptr</tt>. They then do the bitwise
7321 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
7322 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7323
7324<h5>Examples:</h5>
7325<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7326%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7327%ptr = bitcast i8* %mallocP to i32*
7328 store i32 0x0F0F, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7329%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7330 <i>; yields {i32}:result0 = 0x0F0F</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7331%result1 = call i32 @llvm.atomic.load.and.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7332 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7333%result2 = call i32 @llvm.atomic.load.or.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7334 <i>; yields {i32}:result2 = 0xF0</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7335%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7336 <i>; yields {i32}:result3 = FF</i>
7337%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
7338</pre>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7339
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7340</div>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7341
7342<!-- _______________________________________________________________________ -->
7343<div class="doc_subsubsection">
7344 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
7345 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
7346 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
7347 <a name="int_atomic_load_umin">'<tt>llvm.atomic.load.umin.*</tt>' Intrinsic</a><br>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7348</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7349
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7350<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7351
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7352<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7353<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
7354 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
7355 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
7356 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7357
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7358<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7359 declare i8 @llvm.atomic.load.max.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7360 declare i16 @llvm.atomic.load.max.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7361 declare i32 @llvm.atomic.load.max.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7362 declare i64 @llvm.atomic.load.max.i64.p0i64(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7363</pre>
7364
7365<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7366 declare i8 @llvm.atomic.load.min.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7367 declare i16 @llvm.atomic.load.min.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7368 declare i32 @llvm.atomic.load.min.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7369 declare i64 @llvm.atomic.load.min.i64.p0i64(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7370</pre>
7371
7372<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7373 declare i8 @llvm.atomic.load.umax.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7374 declare i16 @llvm.atomic.load.umax.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7375 declare i32 @llvm.atomic.load.umax.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7376 declare i64 @llvm.atomic.load.umax.i64.p0i64(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7377</pre>
7378
7379<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7380 declare i8 @llvm.atomic.load.umin.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7381 declare i16 @llvm.atomic.load.umin.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7382 declare i32 @llvm.atomic.load.umin.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7383 declare i64 @llvm.atomic.load.umin.i64.p0i64(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7384</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7385
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7386<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7387<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7388 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7389 original value at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7390
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7391<h5>Arguments:</h5>
7392<p>These intrinsics take two arguments, the first a pointer to an integer value
7393 and the second an integer value. The result is also an integer value. These
7394 integer types can have any bit width, but they must all have the same bit
7395 width. The targets may only lower integer representations they support.</p>
7396
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7397<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7398<p>These intrinsics does a series of operations atomically. They first load the
7399 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
7400 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
7401 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7402
7403<h5>Examples:</h5>
7404<pre>
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]7405%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7406%ptr = bitcast i8* %mallocP to i32*
7407 store i32 7, %ptr
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7408%result0 = call i32 @llvm.atomic.load.min.i32.p0i32(i32* %ptr, i32 -2)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7409 <i>; yields {i32}:result0 = 7</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7410%result1 = call i32 @llvm.atomic.load.max.i32.p0i32(i32* %ptr, i32 8)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7411 <i>; yields {i32}:result1 = -2</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7412%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32(i32* %ptr, i32 10)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7413 <i>; yields {i32}:result2 = 8</i>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7414%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32(i32* %ptr, i32 30)
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7415 <i>; yields {i32}:result3 = 8</i>
7416%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7417</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7418
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]7419</div>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7420
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7421
7422<!-- ======================================================================= -->
7423<div class="doc_subsection">
7424 <a name="int_memorymarkers">Memory Use Markers</a>
7425</div>
7426
7427<div class="doc_text">
7428
7429<p>This class of intrinsics exists to information about the lifetime of memory
7430 objects and ranges where variables are immutable.</p>
7431
7432</div>
7433
7434<!-- _______________________________________________________________________ -->
7435<div class="doc_subsubsection">
7436 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7437</div>
7438
7439<div class="doc_text">
7440
7441<h5>Syntax:</h5>
7442<pre>
7443 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7444</pre>
7445
7446<h5>Overview:</h5>
7447<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7448 object's lifetime.</p>
7449
7450<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7451<p>The first argument is a constant integer representing the size of the
7452 object, or -1 if it is variable sized. The second argument is a pointer to
7453 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7454
7455<h5>Semantics:</h5>
7456<p>This intrinsic indicates that before this point in the code, the value of the
7457 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
Nick Lewyckyd20fd592009-10-27 16:56:58 +0000[diff] [blame]7458 never be used and has an undefined value. A load from the pointer that
7459 precedes this intrinsic can be replaced with
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7460 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7461
7462</div>
7463
7464<!-- _______________________________________________________________________ -->
7465<div class="doc_subsubsection">
7466 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7467</div>
7468
7469<div class="doc_text">
7470
7471<h5>Syntax:</h5>
7472<pre>
7473 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7474</pre>
7475
7476<h5>Overview:</h5>
7477<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7478 object's lifetime.</p>
7479
7480<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7481<p>The first argument is a constant integer representing the size of the
7482 object, or -1 if it is variable sized. The second argument is a pointer to
7483 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7484
7485<h5>Semantics:</h5>
7486<p>This intrinsic indicates that after this point in the code, the value of the
7487 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7488 never be used and has an undefined value. Any stores into the memory object
7489 following this intrinsic may be removed as dead.
7490
7491</div>
7492
7493<!-- _______________________________________________________________________ -->
7494<div class="doc_subsubsection">
7495 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7496</div>
7497
7498<div class="doc_text">
7499
7500<h5>Syntax:</h5>
7501<pre>
7502 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7503</pre>
7504
7505<h5>Overview:</h5>
7506<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7507 a memory object will not change.</p>
7508
7509<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7510<p>The first argument is a constant integer representing the size of the
7511 object, or -1 if it is variable sized. The second argument is a pointer to
7512 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7513
7514<h5>Semantics:</h5>
7515<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7516 the return value, the referenced memory location is constant and
7517 unchanging.</p>
7518
7519</div>
7520
7521<!-- _______________________________________________________________________ -->
7522<div class="doc_subsubsection">
7523 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7524</div>
7525
7526<div class="doc_text">
7527
7528<h5>Syntax:</h5>
7529<pre>
7530 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7531</pre>
7532
7533<h5>Overview:</h5>
7534<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7535 a memory object are mutable.</p>
7536
7537<h5>Arguments:</h5>
7538<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]7539 The second argument is a constant integer representing the size of the
7540 object, or -1 if it is variable sized and the third argument is a pointer
7541 to the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]7542
7543<h5>Semantics:</h5>
7544<p>This intrinsic indicates that the memory is mutable again.</p>
7545
7546</div>
7547
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]7548<!-- ======================================================================= -->
7549<div class="doc_subsection">
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7550 <a name="int_general">General Intrinsics</a>
7551</div>
7552
7553<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7554
7555<p>This class of intrinsics is designed to be generic and has no specific
7556 purpose.</p>
7557
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7558</div>
7559
7560<!-- _______________________________________________________________________ -->
7561<div class="doc_subsubsection">
7562 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7563</div>
7564
7565<div class="doc_text">
7566
7567<h5>Syntax:</h5>
7568<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7569 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7570</pre>
7571
7572<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7573<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7574
7575<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7576<p>The first argument is a pointer to a value, the second is a pointer to a
7577 global string, the third is a pointer to a global string which is the source
7578 file name, and the last argument is the line number.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7579
7580<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7581<p>This intrinsic allows annotation of local variables with arbitrary strings.
7582 This can be useful for special purpose optimizations that want to look for
7583 these annotations. These have no other defined use, they are ignored by code
7584 generation and optimization.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7585
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7586</div>
7587
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7588<!-- _______________________________________________________________________ -->
7589<div class="doc_subsubsection">
Tanya Lattner0186a652007-09-21 23:57:59 +0000[diff] [blame]7590 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7591</div>
7592
7593<div class="doc_text">
7594
7595<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7596<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7597 any integer bit width.</p>
7598
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7599<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7600 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7601 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7602 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7603 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7604 declare i256 @llvm.annotation.i256(i256 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7605</pre>
7606
7607<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7608<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7609
7610<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7611<p>The first argument is an integer value (result of some expression), the
7612 second is a pointer to a global string, the third is a pointer to a global
7613 string which is the source file name, and the last argument is the line
7614 number. It returns the value of the first argument.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7615
7616<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7617<p>This intrinsic allows annotations to be put on arbitrary expressions with
7618 arbitrary strings. This can be useful for special purpose optimizations that
7619 want to look for these annotations. These have no other defined use, they
7620 are ignored by code generation and optimization.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7621
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7622</div>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7623
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7624<!-- _______________________________________________________________________ -->
7625<div class="doc_subsubsection">
7626 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7627</div>
7628
7629<div class="doc_text">
7630
7631<h5>Syntax:</h5>
7632<pre>
7633 declare void @llvm.trap()
7634</pre>
7635
7636<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7637<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7638
7639<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7640<p>None.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7641
7642<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7643<p>This intrinsics is lowered to the target dependent trap instruction. If the
7644 target does not have a trap instruction, this intrinsic will be lowered to
7645 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7646
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7647</div>
7648
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7649<!-- _______________________________________________________________________ -->
7650<div class="doc_subsubsection">
Misha Brukman50de2b22008-11-22 23:55:29 +0000[diff] [blame]7651 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7652</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7653
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7654<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7655
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7656<h5>Syntax:</h5>
7657<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7658 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7659</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7660
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7661<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7662<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7663 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7664 ensure that it is placed on the stack before local variables.</p>
7665
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7666<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7667<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7668 arguments. The first argument is the value loaded from the stack
7669 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7670 that has enough space to hold the value of the guard.</p>
7671
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7672<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7673<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7674 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7675 stack. This is to ensure that if a local variable on the stack is
7676 overwritten, it will destroy the value of the guard. When the function exits,
7677 the guard on the stack is checked against the original guard. If they're
7678 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7679 function.</p>
7680
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7681</div>
7682
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7683<!-- _______________________________________________________________________ -->
7684<div class="doc_subsubsection">
7685 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7686</div>
7687
7688<div class="doc_text">
7689
7690<h5>Syntax:</h5>
7691<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7692 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;type&gt;)
7693 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;type&gt;)
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7694</pre>
7695
7696<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7697<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information
Eric Christopher3070e162010-01-08 21:42:39 +0000[diff] [blame]7698 to the optimizers to discover at compile time either a) when an
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7699 operation like memcpy will either overflow a buffer that corresponds to
7700 an object, or b) to determine that a runtime check for overflow isn't
7701 necessary. An object in this context means an allocation of a
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]7702 specific class, structure, array, or other object.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7703
7704<h5>Arguments:</h5>
7705<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]7706 argument is a pointer to or into the <tt>object</tt>. The second argument
7707 is a boolean 0 or 1. This argument determines whether you want the
7708 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
7709 1, variables are not allowed.</p>
7710
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7711<h5>Semantics:</h5>
7712<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]7713 representing the size of the object concerned or <tt>i32/i64 -1 or 0</tt>
7714 (depending on the <tt>type</tt> argument if the size cannot be determined
7715 at compile time.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]7716
7717</div>
7718
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]7719<!-- *********************************************************************** -->
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]7720<hr>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7721<address>
7722 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]7723 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7724 <a href="http://validator.w3.org/check/referer"><img
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Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7726
7727 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencerca058542006-03-14 05:39:39 +0000[diff] [blame]7728 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7729 Last modified: $Date$
7730</address>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]7731
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]7732</body>
7733</html>